Highly efficient and stereoselective radical addition of tertiary amines to electron-deficient alkenes - Application to the enantioselective synthesis of necine bases
S. Bertrand et al., Highly efficient and stereoselective radical addition of tertiary amines to electron-deficient alkenes - Application to the enantioselective synthesis of necine bases, EUR J ORG C, (12), 2000, pp. 2227-2238
A convenient and highly efficient method for the regio- and stereoselective
addition of tertiary amines to electron-deficient alkenes has been elabora
ted. It is based on a radical chain reaction of alpha-aminyl radicals with
alkenes, induced by a photoelectron transfer process between tertiary amine
s 2a-j and excited electron donor substituted phenyl ketones. The influence
of the nature of the amino substituents and of the alkene on the reaction
have been examined. In the presence of (5R)-5-menthyloxy-2-(5H)-furanone (1
) as electron-deficient alkene, the addition of N-alkylpyrrolidines 2a-e oc
curred with a complete facial selectivity and up to 94% isolated yields. Th
is method has been applied to a fast, efficient and enantioselective synthe
sis of necine bases.