Molybdenum(II)- and Tungsten(II)-Catalyzed Allylic Substitution
作者:Andrei V. Malkov、Ian R. Baxendale、Dalimil Dvořák、Darren J. Mansfield、Pavel Kočovský
DOI:10.1021/jo9821776
日期:1999.4.1
The molybdenum(II) complexes Mo(CO)(5)(OTf)(2) (7a), [Mo(CO)(4)Br(2)](2) (8a), their tungsten(II) congeners 7b and 8b, and bimetallic complex Mo(CO)(3)(MeCN)(2)(SnCl(3))Cl (9a) have been found to catalyze the C-C bond-forming allylic substitution with silyl enol ethers derived from beta-dicarbonyls (e.g., 16 + 30 --> 46) or from simple ketones (e.g., 16 + 32 --> 50), aldehydes, and esters as nucleophiles
alkoxyalkylations, and aldehyde enolate allylations proceeding with low catalyst loading (0.1 mol %–5 mol %) is described. The reactions are complete within short times and can even be performed without solvent and under ambient conditions. The mechanism of the reaction was investigated by deuterium labeling and cross-over studies.
The first tertiary alkylations, alkoxyalkylations, and aldehyde enolate allylations are described proceeding with low catalyst loading (0.1 mol % to 5 mol %). The reactions proceed in short times, can be performed without solvent and under ambient conditions.