Despite significant advances in the synthesis of axially chiral compounds, the development of alkene-based atropisomers remains challenging due to their inherently low rotational energy barriers and configurational instability. Herein, we describe a novel radical-mediated strategy for constructing axially chiral scaffolds based on five-membered cyclic vinyl sulfinamides. This transformation proceeds through a photoinduced difunctionalization of chiral propargyl sulfinamides, followed by cyclization, under catalyst-free conditions. Stereocontrol is achieved through chirality transfer from the sulfur stereocenter during radical homolytic substitution (SHi) and is further enhanced by a spontaneous diastereomeric enrichment process. Density functional theory calculations provide mechanistic insights into the origin of these serendipitous findings. The resulting product can be readily transformed into a novel class of axially chiral P,S-ligands, which demonstrate promising catalytic activity.
Chen et al. (Fri,) studied this question.