A9 -Capnellene

On the basis of the examples addressed thus far, it is clear that radical reactions can accomplish manifold transformations in organic synthesis. One of the outstanding achievements of synthetic radical chemistry is the development of synthetic strategies based on controlled, tandem radical cyclizations. The efficiency of such strategies is exemplified in the substantial and elegant synthetic work of D. P. Curran and his group.54 The remainder of this chapter will address the concise total syntheses of ( )-hirsutene [( )-1]55 and ( )-A9(12)-capnellene [( )-2]56 by the Curran group. 

Scheme 30. Curran s synthesis of ( )-A9<12,-capnellene [( )-2] construction of intermediate 155.

The key steps in Mehta s synthesis of (+)-A9(12)-capnellene (408), also constitute a formal olefin metathesis reaction. 

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