 Professor, Born 1943
B.S. 1964, University of Alberta
Ph.D. 1968, University of California-Los Angeles
Room: 8112a
Phone: 608-262-5794
Email: reich@chem.wisc.edu
Position: Professor
“Reactivity of Individual Organolithium Aggregates – a RINMR Study of n-Butyllithium and 2-Methoxy-6-(methoxymethyl)phenyllithium, Amanda C. Jones, Aaron W. Sanders, Martin J. Bevan and Hans J. Reich, J. Am. Chem. Soc. 2007, 129, 3492-3493. Studies on the Reactive Species in Fluoride-Mediated Carbon-Carbon Bond Forming Reactions: Carbanion Formation by Desilylation with Fluoride and Enolates, Margaret M. Biddle and Hans J. Reich, J. Org. Chem. 2006, 71, 4031-4039. Amine and Ether Chelated Aryllithium Reagents - Structure and Dynamics, Hans J. Reich, Wayne S. Goldenberg, Aaron W. San¬ders, Kevin L. Jantzi and C. Christoph Tzschucke, J. Am. Chem. Soc. 2003, 125, 3509-3521. The Effect of HMPA on the Reactivity of Epoxides, Aziridines and Alkyl Halides with Organolithium Reagents, H. J. Reich, A. W. Sanders, A. T. Fiedler, and M. J. Bevan, J. Am. Chem. Soc. 2002, 124, 13386-13387. Are Ate Complexes True Intermediates in the Lithium-Metalloid Exchange? Subtle Effects of Ion Pair Structure in Lithium-Tellurium and Lithium-Selenium Exchange Reactions, Hans J. Reich, Martin J. Bevan, Birgir Ö. Gudmundsson and Craig L. Puckett, Angew. Chem. Int. Ed. Engl. 2002, 41, 3436-3439. The Regioselectivity of Addition of Organolithium Reagents to Enones and Enals: The Role of HMPA, W. H. Sikorski and H. J. Reich, J. Am. Chem. Soc. 2001, 123, 6527-6535. "Chelated Aryllithium Reagents -- Ring Size and Chelating Group Effects," H. J. Reich, W. S. Goldenberg, A. W. Sanders and C. C. Tzschucke, Org. Letters 2001, 3, 33-36. Solution Structure and Stereochemistry of Alkyl- and Silyl-Substituted Allenyl-Propargyllithium Reagents, Hans J. Reich, Johnathan E. Holladay, Tamara G. Walker and Jennifer L. Thompson, J. Am. Chem. Soc. 1999, 121, 9769-9780. Tris(trimethylsilyl)methane as an Internal 13C NMR Chemical Shift Thermometer. William H. Sikorski, Aaron W. Sanders and Hans J. Reich, Magn. Resonan. Chem. 1998, 36, S118-S124. Triple Ion Formation in Localized Organolithium Reagents, Hans J. Reich, William H. Sikorski, Birgir . Gudmundsson and Robert R. Dykstra, J. Am. Chem. Soc. 1998, 120, 4035-4036. "Aggregation and Reactivity of Phenyllithium Solutions," Hans J. Reich, D. Patrick Green, Marco A. Medina, Wayne S. Goldenberg, Birgir ". Gudmundsson, Robert R. Dykstra and Nancy H. Phillips, J. Am. Chem. Soc. 1998, 120, 7201"7210. - "Dynamics of Solvent Exchange in Organolithium Reagents. Lithium as a Center of Chirality," Hans J. Reich and Klaus J. Kulicke, J. Am. Chem. Soc. 1996, 118, 273"274.
- The Origin of Regioselectivity in an Allenyllithium Reagent, Hans J. Reich, Johnathan E. Holladay, J. Derek Mason and William H. Sikorski, J. Am. Chem. Soc. 1995, 117, 12137"12150.
- Synthesis of 2,3-Disubstituted 1,3-Butadienes from Organotin Precursors and Butadienyl Lithium Reagents. Diels-Alder Reactivity, H. J. Reich, I. L. Reich, K. E. Yelm, J. E. Holladay and D. Gschneidner, J. Am. Chem. Soc. 1993, 115, 6625-35.
- A Nuclear Magnetic Resonance Spectroscopic Technique for the Characterization of Lithium Ion Pair Structures in THF and THF/HMPA Solution, Hans J. Reich, Joseph P. Borst, Robert R. Dykstra and D. Patrick Green J. Am. Chem. Soc. 1993, 115, 8728-41.
- The Lithium-Tin Exchange Reaction. Stereochemistry at Tin, H. J. Reich, J. P. Borst, M. B. Coplien and N. H. Phillips. J. Am. Chem. Soc. 1992, 114, 6577.
- Stereochemistry of a Cyclohexyllithium Reagent. A Case of Higher Configurational Stability in Strongly Coordinating Media, Hans J. Reich, Marco A. Medina and Michael D. Bowe, J. Am. Chem. Soc. 1992, 114, 11003.
- Silyl Ketone Chemistry. Preparation and Reactions of Silyl Allenol Ethers. Diels-Alder Reaction of Siloxy Vinylallenes Leading to Sesquiterpenes, Hans J. Reich, Eric K. Eisenhart, Richard E. Olson, and Martha J. Kelly, J. Am. Chem. Soc. 1986, 108, 7791.
- Organoselenium Chemistry. Conversion of Ketones to Enones by Selenoxide syn-Elimination, Hans J. Reich, James M. Renga and Ieva L. Reich, J. Am. Chem. Soc. 1975, 97, 5434.
| Research Description
Our research effort is directed towards the study of organometallic and organometalloid compounds with the goal of deepening our understanding of these materials and thus improve and extend their chemistry.
Most carbon-carbon bond forming processes involve the interaction of carbanionic centers with carbon electrophiles like carbonyl compounds, epoxides, aziridines, alkyl halides, activated alkenes and many others. Organolithium reagents are probably the single most important source of carbanionic species, both directly as well as indirectly as precursors to other organometallic reagents (Cu, B, Si, Sn, etc). They have long played an important role in synthetic organic chemistry, and a vast literature provides many complex recipes for preparing and utilizing them. However, the basis for much of what we do in the laboratory when we prepare and use lithium reagents is empirical rather than based on firm mechanistic and structural insights. We are trying to replace the “art” in the chemistry of these organometallic reagents with science.
Some of the reactivity issues we are interested in are the following: What determines whether an organometallic reagent adds 1,2 or 1,4 to an α,β-unsaturated carbonyl compound? Why do lithium halides sometimes have such dramatic effects on organolithium reactions? What role does catalysis by lithium cation play in reactions? What intermediate species are formed during lithium-metalloid exchange reactions and transmetalations and what are their reactivities? What role do different organolithium aggregates play in the selectivity and reactivity of these reagents? How do coordinating solvents and co-solvents such as THF, TMEDA, HMPA, crown ethers and others play their important roles in fine tuning the stereochemistry and regiochemical selectivity of organolithium reagents? How do chelating appendages affect structure and reactivity? What factors influence the configurational stability of organolithium reagents?
The key to unraveling these complexities lies in understanding the organolithium reagents themselves. We perform extensive multinuclear variable temperature NMR studies of organolithium solutions to establish Li-C connectivity, aggregation state, and the dynamics of species interconversion as a function of solvent and solvent additive. These are combined with kinetic studies using a recently developed Rapid Injection NMR apparatus which allows determination of reaction rates on a time scale of seconds at temperatures as low as -135 C. This apparatus allowed some of the first accurate measurements of the reactivity of individual organolithium aggregates towards common electrophiles, as well as the reactivities of individual conformational isomers of an amide.
Last Updated: May 5, 2008
Arfvedson-Schlenk Prize in Lithium Chemistry, German Chemical Society, 2007 University of Wisconsin Mid-Career Award, 1996 Evan P. Helfaer Professor of Chemistry, University of Wisconsin-Madison (1991-1996). Upjohn Teaching Award, University of Wisconsin, 1994 Two-Year Extension for Special Creativity, 1991-1994 Alfred P. Sloan Fellow, 1975-79 Canadian National Research Council Postdoctoral Fellowship, 1968-70 Woodrow Wilson National Fellowship, 1964-65
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