Rhodium-Catalyzed and Zinc(II)-Triflate-Promoted Asymmetric Hydrogenation of Tetrasubstituted α,β-Unsaturated Ketones
作者:Joel R. Calvin、Michael O. Frederick、Dana L. T. Laird、Jacob R. Remacle、Scott A. May
DOI:10.1021/ol203264a
日期:2012.2.17
The asymmetrichydrogenation of tetrasubstitutedα,β-unsaturatedketones has been accomplished using an in situ formed rhodium-Josiphos catalyst. The reaction is enhanced by addition of catalytic zinc(II) triflate, which significantly improves turnover frequency while suppressing epimerization of the products.
Palladium catalyzed stereoselective cross-couplings and acylations of chiral secondary diorganozincs
作者:Andreas Boudier、Paul Knochel
DOI:10.1016/s0040-4039(98)02581-7
日期:1999.1
Cyclic and open-chain trisubstituted olefins were hydroborated with (−)-IpcBH2 and stereoselectively transmetalated to the corresponding chiral zinc reagents with excellent diastereoselectivity and good enantioselectivity. The palladium(0) catalyzed cross-coupling with alkenyl iodides or acyl chlorides proceeds with high retention of configuration in satisfactory overall yields.