Regio- and Stereoselective Au(I)-Catalyzed Intermolecular Hydroalkoxylation of Aryl Allenes
作者:Dong-Mei Cui、Chen Zhang、Ke-Rui Yu
DOI:10.1055/s-0028-1088158
日期:2009.4
In the presence of a catalytic amount of Ph3PAuNO3 and H2SO4, the hydroalkoxylation of allenes with alcohols has been shown to proceed smoothly and give allylic ethers in good yields and high regio- and stereoselectivity.
On the Reduction of α,β-Unsaturated (Group 6) Carbene Complexes by NaBH 4 1
作者:Mar Gómez-Gallego、Marı́a J Mancheño、Pedro Ramı́rez、Carmen Piñar、Miguel A Sierra
DOI:10.1016/s0040-4020(00)00204-0
日期:2000.7
Chromium and tungsten styryl Fischer carbene complexes 12 and 15 were transformed into Z-vinyl ether 13 and E-allyl ether 14 by NaBH4 reduction in EtOH. Deuterium labeling experiments demonstrate that the reaction occurs by the initial addition of the hydride to the carbene carbon atom, followed by a 1,3-rearrangement of the M(CO)(5) fragment. The process could involve the participation of an eta(3)-allyl chromium intermediate. The reaction is general and has been applied to a series of alpha,beta-unsaturated alkoxy and aminocarbene complexes. In the case of chromium and tungsten alkynyl carbenes 38 and 39, NaBH4 reduction exclusively yields E-allyl ether 14. The intermediacy of an allenyl complex 41 obtained after the 1,3-rearrangement of the metal center is confirmed by deuterium labeling experiments. (C) 2000 Elsevier Science Ltd. All rights reserved.