Borrowing hydrogen alkylation of indenes with alcohols by manganese pincer complex

Abstract

Herein, we report a highly efficient and selective formal C3-alkylation of indenes with a wide range of primary and secondary alcohols catalyzed by PNP-manganese pincer complex. This transformation proceeds via a borrowing hydrogen strategy, utilizing sustainable and abundant alcohols as alkylating agents. The reaction offers good functional group tolerance and regioselectivity, providing a practical and straightforward approach to the synthesis of alkylated indenes. Preliminary mechanistic investigations indicate that the reaction proceeds via a multi-step pathway involving the dehydrogenation of the alcohol to a carbonyl intermediate, followed by cross-condensation, hydrogenation, and isomerization steps to afford the final product.