posted on 1999-02-18, 00:00authored byDerrick L. J. Clive, Don M. Coltart, Yuanxi Zhou
(−)-A58365A (1) and (−)-A58365B (2), which are inhibitors of angiotensin-converting enzyme, were
synthesized from the subunits 9 and 10. These were coupled, and the resulting individual amides
17a,b were converted by ozonolysis into aldehydes 18a,b, which underwent cyclodehydration to
the enamides 19a,b. Treatment with a stannane served to generate the vinyl stannanes 20a,b,
from which ketones 22a,b were produced by protodestannylation and ozonolysis. Base treatment
and hydrogenolysis then afforded (−)-A58365A (1). The intermediates 17a,b were also converted
into aldehydes 26a,b by hydroboration and oxidation, and a similar sequence to that used for (−)-A58365A was then applied in order to complete the first enantiospecific synthesis of the congener,
(−)-A58365B (2).