Stereoselective Nickel-Catalyzed [2+2+2] Cycloaddition of Enynes and Arynes
作者:Mark Lautens、David Candito
DOI:10.1055/s-0030-1261171
日期:2011.9
Examples of stereoselective reactions of aryne intermediates are rare in the literature. A stereoselectivenickel-catalyzed [2+2+2] cycloaddition of 1,6-enynes with aryne intermediates is reported. Excellent stereoselectivities were observed when a substituent is adjacent to the olefin moiety resulting in trans- stereochemistry in the products. This reaction is capable of generating much complexity
Catalytic Asymmetric Synthesis of Chiral Propargylic Alcohols for the Intramolecular Pauson−Khand Cycloaddition
作者:Mark Turlington、Yang Yue、Xiao-Qi Yu、Lin Pu
DOI:10.1021/jo101545v
日期:2010.10.15
aldehydes are used to prepare the propargylic alcohol-based chiral en-ynes. Protection of the propargylic alcohols with either an acetyl or a methyl group allows the resulting en-ynes to undergo the intramolecularPauson−Khandreaction to form the corresponding optically active 5,5- and 5,6-fused bicyclic products with high diastereoselectivity and high enantiomeric purity. In the major product, the propargylic