Synthesis of Bicyclo[n.1.0]alkanes by a Cobalt-Catalyzed Multiple C(sp3 )-H Activation Strategy.

A cobalt-catalyzed dual C(sp3 )-H activation strategy has been developed and it provides a novel strategy for the synthesis of bicyclo[4.1.0]heptanes and bicyclo[3.1.0]hexanes. A key to the success of this reaction is the conformation-induced methylene C(sp3 )-H activation of the resulting cobaltabicyclo[4.n.1] intermediate. In addition, the synthesis of bicyclo[3.1.0]hexane from pivalamide, by a triple C(sp3 )-H activation, has also been demonstrated.