Dual Diselenide/Guanidine-Catalyzed Asymmetric Synthesis of Axially Chiral Styrenes via Dehydrogenative Coupling

Axially chiral styrenes, which represent a class of open-chain olefinic systems distinct from biaryl frameworks, pose considerable synthetic challenges owing to their structural flexibility and low rotational energy barrier. Herein, we developed a cooperative diselenide/guanidine dual catalytic system for the atroposelective synthesis of axially chiral styrenes via dehydrogenative coupling between racemic styrene-type allylic alcohol derivatives and diarylphosphine oxides. This transformation lies in the synergistic interplay of two catalytic components: an electron-deficient diselenide that mediates the phosphorus umpolung process to generate the electrophilic selenium-containing intermediate Int-Se and a chiral guanidine organosuperbase that plays a dual role as a bifunctional catalyst. A variety of valuable axially chiral styrene derivatives are obtained with good yields and high enantioselectivities (up to 97% yield and 99:1 e.r.). The utility of the enantiomerically enriched products is further highlighted by their simple elaboration into other compounds.