Transition Structures of [2,3]-Wittig Rearrangement of 2-Oxa-5-methylhexene-1-carboxylic Acid

Transition structures for [2,3]-Wittig rearrangement of dilithium salts of 2-oxa-4-(Z and E)-methylhexene-1-carboxylic acid (1 and 2, respectively) have been located with ab initio molecular orbital calculation at the level of 6-31G* basis set. The origin of the observed stereoselectivity of [2,3]-Wittig rearrangement of 1 and 2 was clarified.