Chemo- and Regioselectivity-Tunable Pd-Catalyzed Allylic Alkylation of Imines
摘要:
alpha-Carbanions of cyclic and acyclic imines have been successfully applied as nucleophiles in the Pd-catalyzed allylic alkylation reaction. Tuning of chemo- and regioselectivity has been realized by using t-BuOK/THF and LDA/toluene to give branched and linear products, respectively, with high regio- and diastereoselectivities. A plausible mechanism is proposed on the basis of the experimental results and DFT calculations.
Acyclic Stereoselection in the Ortho Ester Claisen Rearrangement
作者:G. William Daub、James P. Edwards、Carol R. Okada、Jana Westran Allen、Claudia Tata Maxey、Matthew S. Wells、Alexandra S. Goldstein、Michael J. Dibley、Clarence J. Wang、Daniel P. Ostercamp、Steven Chung、Paula Shanklin Cunningham、Martin A. Berliner
DOI:10.1021/jo9614250
日期:1997.4.1
The ortho ester Claisen rearrangement of trisubstituted allylicalcohols exhibits significant levels of diastereoselection. In E allylicalcohols, a 1,3-diaxial interaction develops in the chairlike transition state leading to the anti isomer, rendering the reaction syn selective by a factor of 3-5 to 1. In Zallylicalcohols, the 1,3-diaxial interaction develops in the transition state leading to