Pronounced enhancement of stereoselectivity in asymmetric hydrogenation of 2-substituted 2-propen-1-ols by transient acylation
摘要:
In the hydrogenation using a chiral catalyst, Ru2Cl4[(R)-(+)-BINAP](2)NEt(3), aroylation of the allylic hydroxyl group of 2-(hydroxymethyl)4-hydroxy-4-methyl-1-pentene (2b) and 2-(hydroxy-methyl)-3-(1-hydroxycyclohexyl)-1-propene (3b) resulted in pronounced enhancement of asymmetric induction. (C) 1997, Elsevier Science Ltd.
3-methylenetetrahydrofurans and 3-methylenepyrrolidines by addition of 2-(bromozincmethyl)-2-alkenyl ethers or 2-(chloromagnesiomethyl)-2-alkenyl ethers to aldehydes, ketones and imines followed by pd(0)-catalyzed cyclization
作者:Jaap van der Louw、Juul L. van der Baan、Henk Stichter、Gerardus J.J. Out、Franciscus J.J. de Kanter、Friedrich Bickelhaupt、Gerhard W. Klumpp
DOI:10.1016/s0040-4020(01)92280-x
日期:1992.11
Reaction of 2-(bromozincmethyl)-2-alkenyl ethers 1 or 2-(chloromagnesiomethyl)-2-alkenyl ethers 2 with aldehydes, ketones and imines affords the addition products 4 and 8, which undergo Pd(0)-catalyzed cyclization to the 3-methylenetetrahydrofurans 6 (R1 = H) and 3-methylenepyrrolidines 10 (R1 = H). Addition of 1a or 1b to α,β-unsaturated substrates proceeds in the 1,2-mode only. Reaction of the 3-alkyl
In the hydrogenation using a chiral catalyst, Ru2Cl4[(R)-(+)-BINAP](2)NEt(3), aroylation of the allylic hydroxyl group of 2-(hydroxymethyl)4-hydroxy-4-methyl-1-pentene (2b) and 2-(hydroxy-methyl)-3-(1-hydroxycyclohexyl)-1-propene (3b) resulted in pronounced enhancement of asymmetric induction. (C) 1997, Elsevier Science Ltd.