Journal of the American Chemical Society, Vol.130, No.29, 9228-9228, 2008
Enantioselective Claisen rearrangements with a hydrogen-bond donor catalyst
N,N'-Diphenylguanidinium ion associated with the noncoordinating BArF counterion is shown to be an effective catalyst for the [3,3]-sigmatropic rearrangement of a variety of substituted allyl vinyl ethers. Highly enantioselective catalytic Claisen rearrangements of ester-substituted allyl vinyl ethers are then documented using a new C-2-symmetric guanidinium ion derivative.