Publications<\/a>
Research<\/a>
Group Members<\/a><\/div>\n
[\/et_pb_text][\/et_pb_column][et_pb_column type=”3_4″ _builder_version=”4.22.2″ _module_preset=”default” global_colors_info=”{}”][dsm_text_divider header=”Research” text_alignment=”left” color=”#333333″ module_id=”top” _builder_version=”4.22.2″ _module_preset=”default” header_font=”Open Sans|600|||||||” global_colors_info=”{}”][\/dsm_text_divider][et_pb_text _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n
Phosphites and Disulfides<\/a> | NMR<\/a> | Electron-Withdrawing Phosphines<\/a> | Noncoordinating Anions and Diels-Alder Catalysis<\/a> | Organometallic Carbyne, Carbene, and Acyl Clusters<\/a> | X-ray Crystal Structures<\/a><\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n Starting with N-sulfonyl amino acids, we showed that P-chiral trivalent phosphorus compounds such as 1 were readily accessible, and that they do not undergo inversion at phosphorus (A1<\/a>, A2<\/a>, A3<\/a>, A7<\/a>).\u00a0 The inversion barrier in phosphite triesters similarly appears to be high, as evidenced by sulfurization of chiral phosphites during the synthesis of chiral phosphorothioates for antisense oligonucleotides, where a sulfur atom replaces an oxygen on the phosphodiester backbone.\u00a0 We showed that the barrier is virtually the same as that for phosphines, with inversion occurring slowly at 150 \u00b0C, as shown for the equilibrium between\u00a02\u00a0and\u00a03\u00a0(A4<\/a>).\u00a0 We synthesized chiral disulfides (for instance\u00a04\u00a0and\u00a05) as a potential route to chiral sulfurization of phosphorus for chiral phosphorothioate synthesis (A5<\/a>, A6<\/a>).<\/p>\n We recently found the novel route from\u00a0H-phosphonodiamidite\u00a06\u00a0and acid chlorides to give acylphosphonites such as\u00a07, and coupling to give acyl dinucleosides such as\u00a08.\u00a0 While\u00a08\u00a0was expected to epimerize readily by analogy to acyl phosphines, it does not, and the calculated inversion barrier is over 40 kcal\/mol (A8<\/a>).<\/p>\n We recently found the novel route from\u00a0H-phosphonodiamidite\u00a06\u00a0and acid chlorides to give acylphosphonites such as\u00a07, and coupling to give acyl dinucleosides such as\u00a08.\u00a0 While\u00a08\u00a0was expected to epimerize readily by analogy to acyl phosphines, it does not, and the calculated inversion barrier is over 40 kcal\/mol (A8<\/a>).<\/p>\n Hersh, W. H.,\u00a0\u201cSynthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization,\u201d<\/a>\u00a0Beilstein J.Org. Chem.\u00a02015,\u00a011, 184-191. (Thematic Issue on Nucleic Acid Chemistry)<\/p>\n Hersh, W. H.; Lam, S. T.; Moskovic, D. J.; Panagiotakis, A. J. \u201cA Non-Karplus Effect: Evidence from Phosphorus Heterocycles and DFT Calculations of the Dependence of Vicinal Phosphorus-Hydrogen NMR Coupling Constants on Lone-Pair Conformation,\u201d\u00a0J. Org. Chem.\u00a02012,\u00a077, 4968-4979.<\/p>\n Mukhlall, J. A.; Hersh, W. H. \u201cSulfurization of Dinucleoside Phosphite Triesters with Chiral Disulfides,\u201d\u00a0Nucleosides, Nucleotides & Nucleic Acids\u00a02011,\u00a030, 706-725.<\/p>\n Mukhlall, J. A.; Noll, B. C.; Hersh, W. H. \u201cSynthesis of Chiral Disulfides:\u00a0 Potential Reagents for Enantioselective Sulfurization,\u201d\u00a0J. Sulfur Chem.\u00a02011,\u00a032, 199-212.<\/p>\n Mukhlall, J. A.; Hersh, W. H. \u201cMeasurement of the Barrier to Inversion of Configuration in Acyclic Phosphite Triesters,\u201d\u00a0Inorg. Chim. Acta\u00a02011,\u00a0369, 62-70. (special R. G. Bergman issue)<\/p>\n Hersh, W. H.; Klein, L.; Todaro, L. J. \u201cStereoselective Synthesis of P-Chiral Phosphorus Compounds from N-tert-Butoxycarbonyl Amino Acids,\u201d\u00a0J. Org. Chem.\u00a02004,\u00a069, 7355-7358.<\/p>\n Hersh, W. H.; Xu, P.; Simpson, C. K.; Grob, J.; Bickford, B.; Hamdani, M. S.; T., W.; Rheingold, A. L. \u201cSynthesis and Structural Characterization of Trivalent Amino Acid Derived Chiral Phosphorus Compounds,\u201d\u00a0J. Org. Chem.\u00a02004,\u00a069, 2153-2163.<\/p>\n Hersh, W. H.; Xu, P.; Simpson, C. K.; Wood, T.; Rheingold, A. L. \u201cA Chiral N-Sulfonylphosphoramide:\u00a0 Synthesis and X-Ray Crystal Structure of a 1,3,2-oxazaphospholidin-5-one, a Trivalent Electron-Withdrawing Amino Acid-Derived Phosphorus Compound, and Synthesis of Its W(CO)5<\/sub>\u00a0Adduct.,\u201d\u00a0Inorg. Chem.\u00a01998,\u00a037, 384-385.<\/p>\n We have a long-standing interest in unusual NMR spectra, such as that seen in anion “spinning” in phosphine-tungsten complexes where all six fluorine atoms of SbF6<\/sub>–<\/sup>\u00a0couple to phosphorus (B2<\/a>), and more recently in the observation of vastly different vicinal phosphorus-hydrogen coupling constants as a function of lone-pair conformation as shown for\u00a0calculations on CH3<\/sub>OPH2<\/sub>\u00a0below (A7<\/a>).\u00a0 We use\u00a0Gaussian\u00a0DFT calculations to minimize structures, analyze chemical shifts and coupling constants, and currently to develop a scale to accurately predict\u00a031<\/sup>P chemical shifts for novel species. Hersh, W. H.; Lam, S. T.; Moskovic, D. J.; Panagiotakis, A. J. \u201cA Non-Karplus Effect: Evidence from Phosphorus Heterocycles and DFT Calculations of the Dependence of Vicinal Phosphorus-Hydrogen NMR Coupling Constants on Lone-Pair Conformation,\u201d\u00a0J. Org. Chem.\u00a02012,\u00a077, 4968-4979.<\/p>\n Hersh, W. H. \u201cFalse AA’X Spin-Spin Coupling Systems in\u00a013<\/sup>C NMR: Examples Involving Phosphorus and a 20-Year-Old Mystery in Off-Resonance Decoupling,\u201d\u00a0J. Chem. Educ.\u00a01997,\u00a074, 1485-1489.<\/p>\n Honeychuck, R. V.; Hersh, W. H. \u201cObservation of Anion Spinning in the Dynamic\u00a031<\/sup>P NMR Spectra of Fluorine-Bridged SbF6<\/sub>\u00af, BF4<\/sub>\u00af, and PF6<\/sub>\u00af Adducts of R3<\/sub>P(CO)3<\/sub>(NO)W+<\/sup>.\u00a0 Implications for Barriers to Ionization and the Formation of Ion Pairs and Free Ions in Methylene Chloride and Hexane Solution,\u201d\u00a0J. Am. Chem. Soc.\u00a01989,\u00a0111, 6056-6070.<\/p>\n Honeychuck, R. V.; Hersh, W. H. \u201cObservation of a Novel\u00a031<\/sup>P NMR Cis-Influence Series: Implications for the Relative Basicity of PPh3\u00a0<\/sub>and PMe3<\/sub>\u00a0in Tungsten Carbonyl Complexes,\u201d\u00a0Inorg. Chem.\u00a01987,\u00a026,\u00a01826-1828.<\/p>\n Typical triaryl or trialkyl phosphorus ligands in organometallic compounds are relatively electron-rich.\u00a0 We showed that\u00a0N<\/i>-sulfonyl phosphoramides such as\u00a0TosL\u00a0<\/i><\/b>and\u00a0diTosL<\/i><\/b>\u00a0and\u00a01\u00a0above (C1<\/a>, A1<\/a>) are comparable to fluorinated phosphines in electron-withdrawing ability.\u00a0 Rhodium-catalyzed hydroformylation generally gives better results when relatively electron-poor phosphines are used, and we examined a variety of these ligands; results for\u00a0diTosL\u00a0are shown (C2<\/a>, C3<\/a>).<\/p>\n Magee, M. P.; Li, H. Q.; Morgan, O.; Hersh, W. H. \u201cSynthesis of Electron-withdrawing Butane- and Arenesulfonylamino Phosphines and use in Rhodium-catalyzed Hydroformylation,\u201d\u00a0Dalton Transactions\u00a02003, 387-394.<\/p>\n Magee, M. P.; Luo, W.; Hersh, W. H. \u201cElectron-Withdrawing Phosphine Compounds in Hydroformylation Reactions. 1. Syntheses and Reactions Using Mono- and Bis(p-toluenesulfonylamino) Phosphines,\u201d\u00a0Organometallics\u00a02002,\u00a021, 362-372.<\/p>\n Hersh, W. H.; Xu, P.; Simpson, C. K.; Wood, T.; Rheingold, A. L. \u201cA Chiral N-Sulfonylphosphoramide:\u00a0 Synthesis and X-Ray Crystal Structure of a 1,3,2-oxazaphospholidin-5-one, a Trivalent Electron-Withdrawing Amino Acid-Derived Phosphorus Compound, and Synthesis of Its W(CO)5<\/sub>\u00a0Adduct.,\u201d\u00a0Inorg. Chem.\u00a01998,\u00a037, 384-385.<\/p>\n Hersh, W. H.; Xu, P.; Wang, B.; Yom, J. W.; Simpson, C. K. \u201cSynthesis of Tungsten Carbonyl and Nitrosyl Complexes of Monodentate and Chelating Aryl N-Sulfonylphosphoramides, the First Members of a New Class of Electron-Withdrawing Phosphine Ligand.\u00a0 Comparative IR and\u00a013<\/sup>C and\u00a031<\/sup>P NMR Study of Related Phosphorus Complexes,\u201d\u00a0Inorg. Chem.\u00a01996,\u00a035, 5453-5459.<\/p>\n In the 1980’s we discovered a group of tungsten carbonyl nitrosyl Lewis acids that would reversibly bind the so-called “noncoordinating” anions SbF6<\/sub>–<\/sup>, PF6<\/sub>–<\/sup>, and BF4<\/sub>–<\/sup>\u00a0via a bridging fluorine atom (D1<\/a>, D4<\/a>).\u00a0 X-ray structures showed that tungsten coordination stretched the Sb-F, P-F, or B-F bond but did not cleave it from the inorganic Lewis acids SbF5<\/sub>, PF5<\/sub>, and BF3<\/sub>\u00a0(see SbF6<\/sub>–<\/sup>\u00a0adduct\u00a01\u00a0with a Cy3<\/sub>P ligand below).\u00a0\u00a031<\/sup>P and\u00a019<\/sup>F NMR spectra exhibited P-F coupling indicating anion coordination at low temperature, but at higher temperatures anion “spinning” via dissociation to tight ion pairs occurred followed by dissociation to free ions (D1<\/a>, B2<\/a>, D5<\/a>).<\/p>\n The Me3<\/sub>P analogue of\u00a01\u00a0is an efficient Diels-Alder catalyst, activating enones such as acrolein and methyl vinyl ketone by Lewis acid coordination of tungsten to the carbonyl oxygen as seen in the X-ray structure of\u00a02\u00a0(D2<\/a>) with acrolein coordinated to the tungsten cation. We examined chiral analogues such as\u00a03\u00a0and\u00a04\u00a0but have not achieved high yields with high enantioselectivity (D3<\/a>).<\/p>\n Hersh, W. H. \u201cSynthesis and Characterization by\u00a01<\/sup>H,\u00a013<\/sup>C, and\u00a019<\/sup>F NMR of (CH3<\/sub>CN)n<\/sub>(CO)4-n<\/sub>(NO)W(\u03bc-F)BF3<\/sub>\u00a0and [(CH3<\/sub>CN)n+1<\/sub>(CO)4-n<\/sub>(NO)W][BF4<\/sub>] (n=0-2), Tungsten Mononitrosyl Carbonyl Cations with Labile Acetonitrile and [(\u03bc-F)BF3<\/sub>]\u00af Ligands,\u201d\u00a0Inorg. Chem.\u00a01990,\u00a029, 713-722.<\/p>\n Honeychuck, R. V.; Hersh, W. H. \u201cObservation of Anion Spinning in the Dynamic\u00a031<\/sup>P NMR Spectra of Fluorine-Bridged SbF6<\/sub>\u00af, BF4<\/sub>\u00af, and PF6<\/sub>\u00af Adducts of R3<\/sub>P(CO)3<\/sub>(NO)W+<\/sup>.\u00a0 Implications for Barriers to Ionization and the Formation of Ion Pairs and Free Ions in Methylene Chloride and Hexane Solution,\u201d\u00a0J. Am. Chem. Soc.\u00a01989,\u00a0111, 6056-6070.<\/p>\n Honeychuck, R. V.; Hersh, W. H. “Coordination of “Noncoordinating” Anions: Synthesis, Characterization, and X-ray Crystal Structures of Fluorine-Bridged [SbF6<\/sub>]\u00af, [BF4<\/sub>]\u00af, and [PF6<\/sub>]\u00af Adducts of [R3<\/sub>P(CO)3<\/sub>(NO)W]+<\/sup>. An Unconventional Order of Anion Donor Strength,”\u00a0Inorg. Chem.\u00a0<\/i>1989<\/b>,\u00a028<\/i>, 2869-2886.<\/p>\n Bonnesen, P. V.; Puckett, C. L.; Honeychuck, R. V.; Hersh, W. H. \u201cCatalysis of Diels-Alder Reactions by Low Oxidation State Transition Metal Lewis Acids: Fact and Fiction,\u201d\u00a0J. Am. Chem. Soc.\u00a01989,\u00a0111, 6070-6081.<\/p>\n Honeychuck, R. V.; Bonnesen, P. V.; Farahi, J.; Hersh, W. H. \u201cCatalysis of Diene Polymerization and Diels-Alder Reactions by an Octahedral Tungsten Nitrosyl Lewis Acid.\u00a0 X-ray Crystal Structure of the\u00a0\u03b71<\/sup>-Acrolein Complex (cis-Me3<\/sub>P)(trans-NO)(CO)3<\/sub>W-O=C(H)-C(H)=CH2<\/sub>,\u201d\u00a0J. Org. Chem.\u00a01987,\u00a052, 5293-5296.<\/p>\n Hersh, W. H. \u201cCoordination of a “Noncoordinating” Anion: X-Ray Crystal Structure and\u00a031<\/sup>P NMR Characterization of a Tungsten Nitrosyl Cation Ligated to SbF6<\/sub>\u00af,\u201d\u00a0J. Am. Chem. Soc.\u00a01985,\u00a0107, 4599-4601.<\/p>\n Metal clusters have long been used to model the behavior of simple organic fragments on a metal surface in order to better understand complex reactions such as the Fisher-Tropsch conversion of CO and H2<\/sub>\u00a0to hydrocarbons.\u00a0 We found a general method for the synthesis of heterodinuclear alkoxycarbynes and discovered a novel oxygen to metal methyl migration reaction (E1<\/a>, E6<\/a>,\u00a0E8<\/a>, E9, E11<\/a>), prepared a related\u00a0\u03bc-acyl (E2, E3), converted the carbynes to “difunctional clusters” containing both a carbyne and alkylidene ligand that couple to give a vinyl ligand (E4<\/a>, E5<\/a>), and examined the kinetics and crossover reactions of these processes (E7<\/a>, E10<\/a>, E12<\/a>).<\/p>\n Hersh, W. H.; Fong, R. H., \u201cCrossover Studies of Methyl Migration from Oxygen to Iron in the Iron-Manganese Methoxycarbyne Complex Cp(CO)Fe(\u03bc-COCH3<\/sub>)(\u03bc-CO)Mn(CO)MeCp,\u201d\u00a0Organometallics\u00a02005,\u00a024, 4179-4189.<\/p>\n Luo, W.; Fong, R. H.; Hersh, W. H. \u201cSynthesis and Oxygen to Iron Methyl Migration Reaction of the Heterodinuclear Methoxycarbyne Complex Cp(CO)Fe(\u03bc-COCH3<\/sub>)(\u03bc-CO)Cr(CO)(\u03b76<\/sup>-C6<\/sub>H6<\/sub>),\u201d\u00a0Organometallics\u00a01997,\u00a016, 4192-4199.<\/p>\n Idmoumaz, H.; Lin, C. H.; Hersh, W. H. \u201cMechanism of Alkyl Migration from Oxygen to Metal in Iron-Manganese Ethoxycarbyne Complexes. Induction of Postcleavage Intermolecular Ethyl Exchange by Hydride Bridging of Mononuclear Iron Species,\u201d\u00a0Organometallics\u00a01995,\u00a014, 4051-4063.<\/p>\n Wang, B.; Hersh, W. H.; Rheingold, A. L. \u201cSynthesis and X-Ray Crystal Structure of the Heterodinuclear Iron-Chromium Carbonyl Nitrosyl Anion Complex [trans-(\u03b75<\/sup>-MeCp) (CO) Fe(\u03bc-CO)2<\/sub>Cr(NO)(\u03b75<\/sup>-Cp)][Ph3<\/sub>PCH3<\/sub>], Conversion to a Heterodinuclear Methoxycarbyne Complex, and Kinetics of Thermally-Induced Oxygen to Iron Methyl Migration,\u201d\u00a0Organometallics\u00a01993,\u00a012, 1319-1330.<\/p>\n Hersh, W. H. \u201cSyntheses and Reactions of Heterodinuclear Alkoxycarbyne Complexes,\u201d In\u00a0Transition Metal Carbyne Complexes; F. R. Kreissl, Ed.; Nato ASI Series C:\u00a0 Mathematical and Physical Sciences, Vol. 392; Kluwer Academic Publishers: Dordrecht, 1993; pp 149-150.<\/p>\n Hersh, W. H.; Hunte, F.; Siegel, S. \u201cKinetic Investigation of Phosphine Exchange in CpFe(CO)(L)CH3<\/sub>\u00a0(L = PPh3<\/sub>, PPh2<\/sub>Me) – Rate of Thermal Formation of the 16-Electron Species CpFe(CO)CH3<\/sub>,\u201d\u00a0Inorg. Chem.\u00a01993,\u00a032, 2968-2971.<\/p>\n Fong, R. H.; Lin, C. H.; Idmoumaz, H.; Hersh, W. H. \u201cSynthesis, Structure, Cis-Trans Isomerization, and Reactions of Heterodinuclear Iron Manganese Anion and Alkoxycarbyne Complexes.\u00a0 X-Ray Crystal Structure of\u00a0cis-(\u03b75<\/sup>-Cp)(CO)Fe(\u03bc-COCH2<\/sub>CH3<\/sub>)(\u03bc-CO)Mn(CO)(\u03b75<\/sup>-MeCp),\u201d\u00a0Organometallics\u00a01993,\u00a012, 503-516.<\/p>\n Fong, R. H.; Hersh, W. H. \u201cStereospecific Synthesis of (\u03bc3<\/sub>-COCH3<\/sub>)(\u03bc2<\/sub>-C(H)CH3<\/sub>)(Cp)(MeCp)Fe2<\/sub>Mn(CO)5<\/sub>, the First Carbyne-Ethylidene Cluster, and Intramolecular Hydrogen Migration to Give (\u03bc2<\/sub>-C(H)OCH3<\/sub>)(\u03bc3-CCH3<\/sub>)(Cp)(MeCp)Fe2<\/sub>Mn(CO)5<\/sub>, the First Carbene-Ethylidyne Cluster,\u201d\u00a0Organometallics\u00a01988,\u00a07, 794-796.<\/p>\n Fong, R. H.; Hersh, W. H. \u201cSynthesis and X-Ray Crystal Structure of (\u03bc3<\/sub>-COCH3<\/sub>)(\u03bc2<\/sub>-CH2<\/sub>)(Cp)(MeCp)Fe2<\/sub>Mn(CO)5<\/sub>, the First Carbyne-Methylene Cluster.\u00a0 Carbon-Carbon Coupling to Give a Methoxyvinyl Cluster,\u201d\u00a0J. Am. Chem. Soc.\u00a01987,\u00a0109, 2843-2845.<\/p>\n Bonnesen, P. V.; Yau, P. K. L.; Hersh, W. H. \u201cOxidative Syntheses of Cyclopentadienyl\u00a0\u03b72<\/sup>-Acyl Complexes and Stereospecific Conversion to an\u00a0\u03b72<\/sup>-Ylide Complex.\u00a0 X-Ray Crystal Structures of Cp(NO)(I)Mo(\u03b72<\/sup>-C(O)-p-tol) and Cp(NO)(I)Mo(\u03b72<\/sup>-C(O)(PMe3<\/sub>)-p-tol),\u201d\u00a0Organometallics\u00a01987,\u00a06,\u00a01587-1590.<\/p>\n Bonnesen, P. V.; Baker, A. T.; Hersh, W. H. \u201cA New Metal-Metal Bond-Forming Reaction: Synthesis, Structure, and Mechanism of Formation of (\u03b75<\/sup>-C5<\/sub>H5<\/sub>)(CO)Fe(\u03bc-C(O)-p-tolyl)(\u03bc-CO)Mo(NO)(\u03b75<\/sup>-C5<\/sub>H5<\/sub>), a Rare\u00a0\u03c0-Bound\u00a0\u03bc-Acyl Compound,\u201d\u00a0J. Am. Chem. Soc.\u00a01986,\u00a0108, 8304-8305.<\/p>\n Fong, R. H.; Hersh, W. H. \u201cSynthesis and Reactions of the First Heterodinuclear Methoxycarbyne Complex (\u03b75<\/sup>-C5<\/sub>H5<\/sub>)(CO)Fe(\u03bc-COCH3<\/sub>)(\u03bc-CO)Mn(CO)(\u03b75<\/sup>-CH3<\/sub>C5<\/sub>H4<\/sub>),\u201d\u00a0Organometallics\u00a01985,\u00a04, 1468-1470.<\/p>\n With the acquisition of a new X-ray diffractometer in 2011, we have carried out a series of structures on our own compounds and as collaborations with colleagues.\u00a0 These structures are just now starting to be published, with more than 10 structures currently in the pipeline.<\/p>\n Chen, Y.; Liu, X.; Lee, M.; Huang, C.; Inoyatov, I.; Chen, Z.; Perl, A. C.; Hersh, W. H., \u201cICl-Induced Intramolecular Electrophilic Cyclization of 1-[4-Methoxy(1,1-biphenyl)2-yl]alkynones\u2014A Facile Approach to Spiroconjugated Molecules,\u201d\u00a0Chemistry \u2013 A European Journal\u00a02013,\u00a019, 9795-9799.<\/p>\n Dana, D.; Davalos, A. R.; Subramaniam, G.; Afzal, N.; Hersh, W. H.; Kumar, S., \u201cA Base-Controlled Regioselective Synthesis of Allyl and Vinyl Phenyl Sulfones,\u201d\u00a0Tetrahedron Lett.\u00a02013,\u00a054, 2717-2721.<\/p>\n She, Z.; Niu, D.; Chen, L.; Gunawan, M. A.; Shanja, X.; Hersh, W. H.; Chen, Y. \u201cSynthesis of Trisubstituted Isoxazoles by Palladium(II)-Catalyzed Cascade Cyclization\u2013Alkenylation of 2-Alkyn-1-one O-Methyl Oximes,\u201d\u00a0J. Org. Chem.\u00a02012,\u00a077, 3627-3633.<\/p>\n 7.\u00a0 Miscellaneous and early papers.<\/p>\n (6)\u00a0\u00a0\u00a0 Kane, S.; Hersh, W. H. \u201cPeriplanar or Coplanar?,\u201d\u00a0J. Chem. Educ.\u00a02000,\u00a077, 1366.<\/p>\n (5)\u00a0\u00a0\u00a0 Hersh, W. H.; Bergman, R. G. \u201cKinetics and Mechanism of Decomposition of a Benzodicobaltacyclohexene: Reversible Dinuclear Elimination of\u00a0o-Xylylene via a Dimetalla-Diels-Alder Reaction,\u201d\u00a0J. Am. Chem. Soc.\u00a01983,\u00a0105, 5846-5859.<\/p>\n (4)\u00a0\u00a0\u00a0 Hersh, W. H.; Hollander, F. J.; Bergman, R. G. \u201cSynthesis, Crystal and Molecular Structures, and Reactions of a Benzodicobaltacyclohexene, a Thermally-Derived Mononuclear\u00a0o-Xylylene Complex, and an Unsymmetrical Phosphine-Derived Dinuclear Complex,\u201d\u00a0J. Am. Chem. Soc.\u00a01983,\u00a0105, 5834-5846.<\/p>\n (3)\u00a0\u00a0\u00a0 Theopold, K. H.; Hersh, W. H.; Bergman, R. G. \u201cBinuclear Metallacycles: Organometallic Ring Systems Containing Two Metal Centers,\u201d\u00a0Israel J. Chem.\u00a01982,\u00a022, 27-29.<\/p>\n (2)\u00a0\u00a0\u00a0 Hersh, W. H.; Bergman, R. G. \u201cSynthesis and Reactions of a Dimetallacyclohexene.\u00a0 Thermal Conversion to an\u00a0o-Xylylene Complex and Phosphine-Induced Conversion to Free\u00a0o-Xylylene and a New Reactive Dinuclear Cobalt Complex,\u201d\u00a0J. Am. Chem. Soc.\u00a01981,\u00a0103, 6992-6994.<\/p>\n (1)\u00a0\u00a0\u00a0 Katz, T. J.; Hersh, W. H. \u201cThe Stereochemistry of the Olefin Metathesis Reaction,\u201d\u00a0Tetrahedron Lett.\u00a01977, 585-588.<\/p>\n1. Chiral phosphites and disulfides – connections to oligonucleotide synthesis (papers A1-7<\/a>) <\/strong><\/h6>\n
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<\/p>\n(A8)<\/h6>\n
(A7)<\/h6>\n
(A6)<\/h6>\n
(A5)<\/h6>\n
(A4)<\/h6>\n
(A3)<\/h6>\n
(A2)<\/h6>\n
(A1)<\/h6>\n
2.\u00a0\u00a031<\/sup>P NMR and spin-spin coupling – experiment and theory (papers\u00a0A7<\/a>,B1-3<\/a>).<\/h6>\n
\u200b<\/p>\n![\"\"](\"https:\/\/www.qc.cuny.edu\/academics\/chem\/wp-content\/uploads\/sites\/32\/2023\/10\/JPH-pic.gif\")
<\/p>\n(A7)<\/h6>\n
(B3)<\/h6>\n
(B2)<\/h6>\n
(B1)<\/h6>\n
3.\u00a0\u00a0Electron-withdrawing phosphines and hydroformylation (papers\u00a0A1<\/a>, C1-3<\/a>).<\/h6>\n
![\"\"](\"https:\/\/www.qc.cuny.edu\/academics\/chem\/wp-content\/uploads\/sites\/32\/2023\/10\/HF-pic.gif\")
<\/p>\n(C3)<\/h6>\n
(C2)<\/h6>\n
(A1)<\/h6>\n
(C1)<\/h6>\n
4.\u00a0\u00a0Coordination of “noncoordinating” anions and Diels-Alder catalysis (papers\u00a0B2<\/a>, D1-5<\/a>).<\/h6>\n
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<\/p>\n(D5)<\/h6>\n
(B2)<\/h6>\n
(D4)<\/h6>\n
(D3)<\/h6>\n
(D2)<\/h6>\n
(D1)<\/h6>\n
5.\u00a0\u00a0Organometallic carbynes, alkylidenes, and acyls (papers\u00a0E1-12<\/a>).<\/h6>\n
![\"\"](\"https:\/\/www.qc.cuny.edu\/academics\/chem\/wp-content\/uploads\/sites\/32\/2023\/10\/Carbyne-pic.gif\")
<\/p>\n(E12)<\/h6>\n
(E11)<\/h6>\n
(E10)<\/h6>\n
(E9)<\/h6>\n
(E8)<\/h6>\n
(E7)<\/h6>\n
(E6)<\/h6>\n
(E5)<\/h6>\n
(E4)<\/h6>\n
(E3)<\/h6>\n
(E2)<\/h6>\n
(E1)<\/h6>\n
6.\u00a0\u00a0X-ray structures (F1-3<\/a>).<\/h6>\n
![\"\"](\"https:\/\/www.qc.cuny.edu\/academics\/chem\/wp-content\/uploads\/sites\/32\/2023\/10\/Collab-X-ray-pics.gif\")
<\/p>\n(F3)<\/h6>\n
(F2)<\/h6>\n
(F1)<\/h6>\n