Development, synthetic scope, and mechanistic studies of the palladium-catalyzed cycloisomerization of functionalized 1,6-dienes in the presence of silane

Journal Article (Journal Article)

A 1:1 mixture of the π-allyl palladium complex (η3-C3H5)Pd(CI)PCy3 (1a) and NaB[3,5-C6H3-(CF3)2]4 in the presence of HSiEt3 catalyzed the cycloisomerization of diethyl diallylmalonate (2b) to form 4,4-dicarbomethoxy-1,2-dimethylcyclopentane (3b) in 98% yield with 98% isomeric purity. The procedure tolerated a range of functionality including esters, ketones, sulfones, protected alcohols, and substitution at the allylic and terminal olefinic carbon atoms. Cycloisomerization of 2b obeyed zero-order kinetics to > 3 half-lives with initial formation of 1,1-dicarboethoxy-4-methyl-3-methylenecyclopentane (4b), followed by secondary isomerization to 3b. Deuterium labeling studies revealed that the conversion of 2b to 4b was accompanied by significant H/D exchange, consistent with an addition/elimination pathway coupled with facile H/D exchange of the Pd-H(D) intermediates with free silane.

Full Text

Duke Authors

Cited Authors

  • Kisanga, P; Widenhoefer, RA

Published Date

  • October 18, 2000

Published In

Volume / Issue

  • 122 / 41

Start / End Page

  • 10017 - 10026

International Standard Serial Number (ISSN)

  • 0002-7863

Digital Object Identifier (DOI)

  • 10.1021/ja001730+

Citation Source

  • Scopus