SUBSTITUTION WITH SULFUR AT THE STERICALLY HINDERED NEOPENTYL POSITION - PREPARATION OF 9-MERCAPTOCAMPHOR AND 9,10-EPITHIOCAMPHOR

A variety of methods for S(N)2 substitution at sterically hindered 9-b romocamphor (2) was tested for the preparation of 9-mercaptocamphor (1 ), a fragrant compound with a roasty note reminiscent of onion. All re agents failed, with the notable exception of potassium thioacetate in N-methylpyrrolidone (for 3 days at 180 degrees C). The peculiar reacti vity pattern of both neopentyl-type 2 and 9,10-dibromocamphor (9) invo lves surprisingly smooth substitution reactions where strain is releas ed. Thus, 9 was transformed into tricyclic 9,10-epithiocamphor 12, as established by X-ray analysis.