Reductive elimination of alkylpalladium formate intermediates formed in enyne cyclizations
摘要:
Various enynes under the palladium catalysts,were successfully cyclized to the alkylpalladium intermediates, which then were reduced by the hydrogen in a formate ligand (C) 1999 Elsevier Science Ltd. All rights reserved.
Regio- and stereoselectivity in palladium-catalyzed cycloreductions of 1,6-enynes in the presence of formic acid or triethylsilane
作者:Chang Ho Oh、Hyung Hoon Jung、Hye Rhyan Sung、Jung Duk Kim
DOI:10.1016/s0040-4020(01)00008-4
日期:2001.2
Palladium catalyzed 1,6-enyne cycloreductions in the presence of 1.2 equiv. of formic acid (method A) would involve cycloalkylpalladium formates which proceed via two consecutive steps: beta -elimination of alkylpalladium intermediates and then reduction at the less hindered olefins regio- and stereoselectivity. Triethylsilane, however, directly reduced the alkylpalladium intermediates to give the corresponding cycloreduced products (method B). (C) 2001 Elsevier Science Ltd. All rights reserved.