Use of the Temporary Connection in Carbenoid Chemistry

A similar tethering system was used to functionalize the A-ring of a number of steroidal derivatives regio- and stereoselectively. However, attempts to extend the reaction to acyclic systems were less successful, providing mixtures of diastereoisomers. 

Transition metal-catalyzed carbenoid insertion into the k system of aryl compounds followed by ring expansion of the resultant [4.1.0]bicyclohepta-2,4-diene provides the 

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