Sa-g 6a-g chemistry in synthesi~.~~.~ We reasoned that strategic placement of a trimethylsilyl group as shown in Scheme I1 could direct the introduction of the new double bond in a Nazarov cyclization to the less substituted position, Le., away from the ring fusion. a The obvious advantages of such an outcome are (1) controlled introduction of potential functionality based on the double bond and (2) ready isomerization of the double bond ...
