Cobalt-Catalyzed Cycloisomerization of 1,6-Enynes and Allyl Propargyl Ethers
作者:Alain Ajamian、James L. Gleason
DOI:10.1021/ol034541f
日期:2003.7.1
6-Enynes and allyl propargyl ethers undergo a cobalt-catalyzed formal 5-endo-dig cyclization to form vinyl cyclopentenes and dihydrofurans, respectively. The use of equimolar amounts of dicobalt octacarbonyl and trimethyl phosphite affords optimum yields and improved selectivity for cycloisomerization vs alkene isomerization.
New entry to the Pauson–Khand reaction: trimethylgermyl group at the triple bond terminus as a latent functional group
作者:Chisato Mukai、Takashi Kozaka、Yukihiro Suzuki、In Jong Kim
DOI:10.1016/j.tet.2004.01.041
日期:2004.3
The Pauson-Khand reaction of enynes possessing a trimethylgermyl group at the alkyne terminus afforded the corresponding bicyclo[3.3.0]octenone and bicyclo[4.3.0]nonenone skeletons in a stereoselective manner. The resulting trimethylgermyl group of the bicyclic compounds was then converted to the iodo group, which was used for further elaboration. Thus, the trimethylgermyl group at the triple bond terminus was shown to be a precursor for other appendages. (C) 2004 Elsevier Ltd. All rights reserved.