Efficient Enantioselective Additions of Terminal Alkynes and Aldehydes under Operationally Convenient Conditions
作者:Dean Boyall、Doug E. Frantz、Erick M. Carreira
DOI:10.1021/ol026282k
日期:2002.7.1
[GRAPHICS]The enantioselective addition reaction of terminal acetylenes and aldehydes mediated by Zn(OTf)(2) and N-methyl ephedrine can be conducted with reagent grade solvent containing 84-1000 ppm H2O. The products can be isolated in high yield and useful enantioselectivities (up to 99% ee).
Catalytic Asymmetric Enyne Addition to Aldehydes and Rh(I)-Catalyzed Stereoselective Domino Pauson–Khand/[4 + 2] Cycloaddition
作者:Wei Chen、Jia-Hui Tay、Jun Ying、Xiao-Qi Yu、Lin Pu
DOI:10.1021/jo3026065
日期:2013.3.15
propargylic alcohols prepared from the catalyticasymmetric enyne addition to aliphatic aldehydes are used to prepare a series of opticallyactive trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the opticallyactive trienynes undergo highly stereoselective domino Pauson–Khand/[4 + 2] cycloaddition to generate opticallyactive multicyclic products. The Rh(I) catalyst
Direct and Stereospecific Synthesis of Allenes via Reduction of Propargylic Alcohols with Cp<sub>2</sub>Zr(H)Cl
作者:Xiaotao Pu、Joseph M. Ready
DOI:10.1021/ja8035527
日期:2008.8.1
Allenes can be synthesized via the direct SN2' addition of hydride to propargylicalcohols. Previous examples of this approach, however, have involved harsh reaction conditions and have suffered from incomplete transfer of central chirality to axial chirality. Here we show that Cp2Zr(H)Cl can react with the zinc or magnesium alkoxides of propargylicalcohols to generate allenes in good yield and in