Lewis acid induced asymmetric prins reactions of chiral acetals with alkenes

Abstract

Me2AlCl induced reaction of acetal 1 with methylenecyclohexane at −78°C gives a 61% yield of 3 as a 7:3 mixture of diastereomers. MeAlCl2 induced reaction of acetal 2 with methylenecyclohexane gives a 53% yield of 6 as a 7:3 mixture of isomers. Reaction of 1 with isoprene gives 7 as a mixture of all 4 possible isomers. Reaction of acetal 8 with methylenecyclohexane gives the conjugate addition product 9 in 70% yield as a 4:1 mixture of isomers. © 1986, Taylor & Francis Group, LLC. All rights reserved.