Starting from a key intermediate for the synthesis of the larger hydroxy ac
id constituent of pamamycin-607 (1), an efficient three-step route to the m
ethyl ester of the smaller fragment of I involving a Yamaguchi lactonizatio
n with concomitant C(2) epimerization was developed. Alternatively, the met
hyl ester of the smaller hydroxy acid portion of I was prepared by direct C
(2) epimerization. (C) 2001 Elsevier Science Ltd. All rights reserved.