A Mild Chemo-Enzymatic Oxidation–Hydrocyanation Protocol
作者:Danielle J. Vugts、Lars Veum、Kanar al-Mafraji、Renske Lemmens、Rob F. Schmitz、Frans J. J. de Kanter、Marinus B. Groen、Ulf Hanefeld、Romano V. A. Orru
DOI:10.1002/ejoc.200500905
日期:2006.4
Oxidation–hydrocyanation of γ,δ-unsaturated alcohols using (immobilised) TEMPO/PhI(OAc)2 in combination with HbHNL proceeds smoothly. After (in situ) protection, the resulting cyanohydrin derivatives were obtained in good overall yields and high ee’s. A mild TEMPO-catalysed oxidation protocol is described that yields β,γ-unsaturated aldehydes without isomerisation of the double bond and that is compatible
(S,S)-N,N-Bis(-α-methylbenzyl)formamide is the first example of chiral formamides that function as Lewis base catalysis to effectively serve catalytic asymmetricsynthesis. The chiral formamide in combination with an additive, HMPA, catalyzes allylations of aliphatic aldehydes with allyl- and crotyltrichlorosilanes with high enantioselectivity (up to 98% ee). In the crotylations with (E)-crotyltrichlorosilane