Chemistry of the Podocarpaceae. XXX. Conversion of 8α,13-Epoxylabd-14-ene into a compound with an ambergris-type odour

Manoyl oxide (1) has been converted into the five-membered oxide (7), a compound with an ambergris-type odour which has been previously prepared from sclareol (13). The route involves the intermediates (14), (15), (17), (10), and (32), and gives an overall yield of 17% from manoyl oxide. The oxide (7) has also been prepared from manoyl oxide in two steps by oxidation with chromium trioxide followed by reduction of the lactone (10) with diborane.