Copper(I) mediated highly diastereoselective conjugate addition of Grignard reagents to functionalised cycloalkenols: a general and efficient route for the stereoselective synthesis of 5- and 6-membered ring trisubstituted cycloalkanols
The conjugateaddition of magnesium cuprates to various 2-silyloxycyclopentene and 2-silyloxycyclohexene carboxylates leads diastereoselectively to related syn–anti cyclopentanols and cyclohexanols in fair overall yields. The β-elimination occurring with free hydroxylic derivatives is also partially or totally avoided by concomitant in situ trapping of the generated enolates. Attempts to rationalise
Alkylation d'acetates de cyclenols fonctionnels (5 et 6 chainons) par les reactifs de grignard et les enolates lithiens catalysee (ou non) par les sels de cuivre (I). Synthese rapide de la (±) mitsugashiwalactone
作者:H. Amri、J. Villieras
DOI:10.1016/s0040-4039(00)96769-8
日期:1987.1
Substitution of 1-ethoxycarbonyl n-hydroxycycloalkenes acetates and silyl ethers (n = 5, 6) by GRIGNARDreagents in the presence of cuprous salt as a catalyst or lithium ester enolates (without catalyst) gives rise to various 1-carbethoxy alkylcycloalkenes. It is applied to a new short stereoselective synthesis of (±) Mitsugashiwalactone (6 steps - 27 % global yield) from a succinaldehyde precursor