Teuahedron Lcttcrs. Vol. 33. No. 33. PP. 47354738.1992 oo4o-4039/92 $5.00 + Priitcd in Great Brirain Pergamon Ress Lid DIRECT SUBSTITUTION OF SECONDARY ALLYLIC ALCOHOLS WITH 0-SILYLATED KETENE ACETALS IN 3.0 M LITHIUM PERCHLORATE-DIETHYL ETHER - AN ALTERNATIVE TO THE [1,3] SIGMATROPIC REARRANGEMENT OF ALLYL VINYL ETHERS Paul A. Grieco,‘Jon L. Collins,l and Kenneth J. Henry, Jr. Department of Chemistry, Indiana University Bloomington, Indiana 47405 Abstract: Allylic alcohols of type 1 undergo unprecedented substitution with 0-silylated ketene acetals in 3.0 M lithium perchlorate-diethyl ether. As a result of our continuing interest in the use of lithium perchlorate in diethyl ether to promote organic reactions,*p3 we wish to report that allylic alcohols of the type depicted in Equation 1 undergo extremely facile substitution in 3.0 M lithium perchlorate-diethyl ether upon addition of the silyl ketene acetal derived from methyl acetate. 4 This unprecedented carbon-carbon bond forming reaction represents a useful alternative to the facile [1,3] sigmatropic rearrangement of ally1 vinyl ethers reported previously (Equation 2).3 ~~~~Df$?O equiv) 3.0 M LiCIO,- E&O I \ + (1) 15 min 90% * :,.-q 5.8 : 1 CO,Me 2 3 3.0 M LiCIO,- Et, 0 lh 86% (2) 4735