Joel M. Hawkins
University of California, Berkeley
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Featured researches published by Joel M. Hawkins.
Science | 1993
Joel M. Hawkins; Axel Meyer
The chiral fullerene C76 was kinetically resolved by asymmetric osmylation providing an example of an optically active allotrope of a pure element. C76 recovered from the treatment of racemic C76 with OsO4 and a chiral alkaloid ligand, showed a specific rotation [α]D of -4000� (> 97 percent enantiomeric excess) and a circular dichroism spectrum corresponding to the ultraviolet spectrum. Regenerated C76 formed by reducing the asymmetrically osmylated C76 with SnCl2 was enriched in the opposite enantiomer. Analysis of the local curvature of the C76 molecule indicated that OsO4 should selectively add to 2 of the 30 types of bonds in C76. This regioselectivity was supported chromatographically and interpreted in terms of the kinetic resolution.
Journal of Organic Chemistry | 1984
Joel M. Hawkins; K. Barry Sharpless
Des cetones prochirales sont reduites de facon asymetrique a −20°C en utilisant un reactif prepare par reaction de LiAlH 4 avec le compose du titre et la N-benzylmethylamine
Tetrahedron Letters | 1990
Joel M. Hawkins; Timothy A. Lewis; Andre S. Raw
Abstract The anions of sulfonate esters derived from acidic alcohols olefinate carbonyl compounds. The dependence of the yield and stereochemistry of olefination on the sulfonate esters alkoxy substituent are consistent with a mechanism where apicophilic alkoxy groups promote olefination via 10-S-5 intermediate 3.
Tetrahedron Letters | 1991
Joel M. Hawkins; Stefan Loren; Young-Kyoon Kim
Abstract The combination of boron trichloride and hydrogen chloride in dichloromethane at 0°C catalyzes facile alkene isomerizations in certain steroid systems which are not affected by HCl in the absence of BCl 3 .
Journal of The Chemical Society, Chemical Communications | 1991
Joel M. Hawkins; Timothy A. Lewis; Stefan Loren; Axel Meyer; James R. Heath; Richard J. Saykally; Frederick J. Hollander
Crystallographic analysis of C60 grown from a hexane solution revealed a structure which is neither hexagonal nor cubic closest packed [space group P63/m, a= 33.54(1), c= 10.113(8)A]; packing models which are consistent with the Patterson map are described.
Journal of Organic Chemistry | 2008
Mark C. Noe; Joel M. Hawkins; Sheri L. Snow; Lilli A. Wolf-Gouveia
The asymmetric synthesis of (2R,3R)-3-methyl-3-hydroxypipecolic acid, a key intermediate in the synthesis of dual MMP-13/aggrecanase inhibitors, is described. The title compound is prepared in seven steps with an overall yield of 41% starting from geraniol. Key steps in the synthesis include Sharpless asymmetric epoxidation, which establishes the chiral centers, and a one-pot oxidative olefin cleavage/reductive amination sequence that closes the piperidine ring.
Science | 1991
Joel M. Hawkins; Axel Meyer; Timothy A. Lewis; Stefan Loren; Frederick J. Hollander
Journal of Organic Chemistry | 1990
Joel M. Hawkins; Timothy A. Lewis; Stefan Loren; Axel Meyer; James R. Heath; Yoko Shibato; Richard J. Saykally
Journal of the American Chemical Society | 1991
Joel M. Hawkins; Stefan Loren; Axel Meyer; Rudi Nunlist
Journal of Organic Chemistry | 1986
Joel M. Hawkins; Gregory C. Fu