Acyl silane directed Cp*Rh(iii)-catalysed alkylation/annulation reactions

Studies into the Cp*Rh(iii)-catalysed hydroarylation of alkenes with aryl acyl silanes led to the discovery of a new synthetic strategy to access unique silicon derived indene frameworks. Rather than protodemetalation of the metal enolate formed following insertion of an alkene into the aryl C-H bond, intramolecular aldol condensation of the acyl silane occurred to generate a series of 2-formyl- and 2-acetyl-3-silyl indenes. This represents only the second example of rhodium-catalysed C-H functionalisation employing acyl silanes as weakly coordinating directing groups and the intramolecular aldol condensation strategy was extended to access analogous silicon derived benzofurans.

Automated summary

Studies on Cp*Rh(iii)-catalyzed hydroarylation of alkenes with aryl acyl silanes revealed a new synthetic strategy to access unique silicon-based indene frameworks and benzofurans. This represents the second example of rhodium-catalyzed C-H functionalization using acyl silanes as directing groups, with intramolecular aldol condensation being the key step in the process.