Reported herein is the first enantioselective total synthesis of pentacyclic triterpenesl in the oleanane series, including the principal members 8-amyrin (l), erythrodiol (2), and oleanolic acid (3), via the key intermediate aegiceradienol (4), itself a natural product. 2 Previous research on the synthesis of 8-amyrins includes a recently described synthesis of (f)-j3- amyrin, 3 the (*)-A13J8-isomer of B-amyrin, 4a and (f)-3-desoxy-l1, 18-dehydro-O-am~ rin. ...
