Allylsilane-interrupted homo-Nazarov cyclization and synthesis of bicyclo[3.2.1]octan-8-ones

The combination of homo-Nazarov cyclization of 2-(tert-butyldiphenylsilylmethyl)cyclopropyl vinyl ketone leading to oxyallyl cation and its subsequent 3+2] capture by allylsilane has been demonstrated as an useful strategy for the construction of functionalized bicyclo3.2.1]octan-8-ones. The 3+2] capture proceeds exclusively in the exo mode to make the overall reaction diastereoselective. The less substituted end of the oxyallyl cation was found to react nearly two times faster than the more substituted end.