1.
J Org Chem
; 62(7): 1970-1975, 1997 Apr 04.
Article
in English
| MEDLINE
| ID: mdl-11671498
ABSTRACT
Mn(OAc)(3)-initiated cyclization of alkynyl ketones in 9-19:1 EtOH/HOAc at 90 degrees C is a useful cyclization procedure in favorable cases. Cyclization of (trimethylsilyl)alkynyl ketone 4e provides 62% of silylalkenes 26 and 27 in the key reaction of a seven-step (16% overall yield) synthesis of gymnomitrol (1) from readily available ketone 23. 9alpha-Hydroxygymnomitryl acetate (2) and 9-oxogymnomitryl acetate (3) have been prepared from gymnomitrol. Cyclization of propargyl cyclohexanones 39a-c provides bicyclic compounds 40-42 in 40-60% yield.