Anti-
-substituted
,
-unsaturated amino acids have been synthesized via a novel design of the Eschenmoser-Claisen rearrangement. Therearrangement gives good isolated yields and excellent diastereoselectivity due to (
Z)-
N,
O-ketene acetal formation and the pseudochairlikeconformations of the reaction intermediates. Upon reductive hydrolysis, important novel amino acids and amino alcohols were synthesizedfor the first time via this methodology.