delta-Amination of Alkyl Alcohols via Energy Transfer Photocatalysis

Amino alcohols play a crucial role in the realm of biologically active compounds due to their functional diversity. In this study, we introduce a metal-free energy transfer (EnT) photocatalytic method for the preparation of 1,4-aminoalcohols from readily available alcohols feedstocks. The key feature of this transformation is the simultaneous generation of an iminyl and oxygen-centered radicals via EnT. The process embraces a fragmentation/decarboxylation/1,5-HAT (hydrogen atom transfer) processes leading to the formation of a C(sp3)-hybridized radical, which undergo a selective radical-radical cross-coupling or a radical chain event to yield the desired products. In addition, the protocol was also found suitable for N-tosylamines giving rise to 1,4-diamines. Our approach combines experimental mechanistic investigations with detailed computational studies using density functional theory (DFT) that provide insights into the reaction mechanism. This innovative method offers a novel route for the preparation of δ-amino alkyl alcohols and amines.