Functionalized esters as bis-electrophiles in a silicon-induced domino synthesis of annulated carbocycles

The reaction Of silyl-substituted carbanion 1b with arene-1,2-dicarboxylates 6, 15 yields indenone derivatives 11, 16 in a domino process involving silyl C -> O migration and elimination. However, in a competing pathway, the initial addition of 1b leads to lactone formation (8, 17). Substrates 26, 38 containing an ester group and a bromine substituent react with 1b under Substitution of the halogen not allowing silyl migration. But desilylation with TBAF gives reactive carbanions providing benzo-annulated cycloalkanones 29, 40. (C) 2009 Elsevier Ltd. All rights reserved.