Stereogenic S-Induced Generation of Axially Chiral Cyclic Vinyl Sulfinamides and Serendipitous Diastereomeric Enrichment

High Resolution Image Download MS PowerPoint Slide 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 (S H i) 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.