A lutidine-promoted photoredox catalytic atom-transfer radical cyclization reaction for the synthesis of 4-bromo-3,3-dialkyl-octahydro-indol-2-ones

Reported herein is a visible-light-catalyzed photoredox atom-transfer radical cyclization (ATRC) halo-alkylation of 1,6-dienes with α-halo-ketones as the ATRC reagent. This process exhibits high atom economy, high step economy, and high redox economy, which can directly construct a 4-bromo-3,3-dialkyl-octahydro-indol-2-one core under mild conditions in one pot, and lutidine is found to be the key promoter for this ATRC process. We describe an atom-transfer radical cyclization strategy, with which a variety of 4-bromo-3,3-dialkyl-octahydro-indol-2-one compounds can be easily accessed via a lutidine-promoted photoredox catalytic halo-alkylation of 1,6-dienes.