Ester-enolate Claisen rearrangement of proline-containing α-acyloxy-α-vinylsilane. Synthesis of pyrrolidine-fused glutamate analogs

The stereoselective syntheses of pyrrolidine-fused aspartate and glutamate analogs, (S)-α-carboxymethyl-proline 3 and (S)-α-2-carboxyethyl-proline 4, using a chirality-transferring ester-enolate Claisen rearrangement of α-vinyl-α-acyloxysilane having a Boc-Pro as an acyloxy group, are described. The stereochemical outcome of the proline ester-derived ester-enolate Claisen rearrangement is also disclosed.