A short, formal, biomimetic synthesis of (+/-)-polygalolides A and B.
[reaction: see text] Reaction of bisacetoxy pyranone 9 with Et3N gave 3-oxidopyrylium ylide 10, which underwent a stereo- and regiospecific [5 + 2] cycloaddition with alpha-methylenebutyrolactone to afford 16 (34%). Treatment of 16 with Cs2CO3 resulted in hydrolysis of the lactone and acetate and conjugate addition of the hydroxyethyl group to the enone. Lactonization on acidification afforded 4 (57%), completing a two-step, formal synthesis of polygalolides A and B.
Snider
Barry B
BB
Department of Chemistry MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA. snider@brandeis.edu
Wu
Xiaoxing
X
Nakamura
Seiichi
S
Hashimoto
Shunichi
S
D032701:Biomimetics; D003508:Cycloheptanes / Q000737:chemistry; D015394:Molecular Structure; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry
D003508:Cycloheptanes; D010636:Phenols; C414696:cartorimine; C476753:polygalolide A; C476754:polygalolide B