摘要:
The azaallyl cation-mediated [4 + 3] cycloaddition with spiro[2.4]hepta-4,6-diene by the procedure of Schmid provides the tricyclic cycloadducts of general type 3. The keto bridge of the cycloadducts 17c, 21, and 22 has been cleaved by PhI(OAc)(2)-I-2 (Suarez cleavage), which involves P-fragmentation of an alkoxy radical, to furnish iodo lactones 19, 32, and 30a,b, respectively. Subsequent oxidation of these alkyl iodides has been investigated to develop a new synthetic route for bridgehead olefins (i.e., 33) of medium-sized carbocycles.