Showing papers by "Shaofa Sun published in 2021"

Organocatalytic atroposelective heterocycloaddition to access axially chiral 2-arylquinolines

Abstract: Axially chiral heterobiaryls play a vital role in asymmetric synthesis and drug discovery. However, there are few reports on the synthesis of atropisomeric heterobiaryls compared with axially chiral biaryls. Thus, the rapid enantioselective construction of optically active heterobiaryls and their analogues remains an attractive challenge. Here, we report a concise chiral amine-catalyzed atroposelective heterocycloaddition reaction of alkynes with ortho-aminoarylaldehydes, and obtain a new class of axially chiral 2-arylquinoline skeletons with high yields and excellent enantioselectivities. In addition, the axially chiral 2-arylquinoline framework with different substituents is expected to be widely used in enantioselective synthesis. 2-Arylquinoline derivatives are key components of many enantioselective catalysts, but existing synthetic routes are few in number. Here atroposelective aminocatalytic aza-Michael addition of amino-benzaldehydes to iminium intermediates yields single-enantiomer 2- arylquinoline derivatives with high selectivity

Highly diastereoselective spiro-cyclopropanation of 2-arylidene-1,3-indanediones and dimethylsulfonium ylides

Abstract: A highly diastereoselective spiro-cyclopropanation reaction of 2-arylidene-1,3-indanediones and dimethylsulfonium ylides has been developed via base-induced annulation. This efficient and simple protocol features simple operations, mild conditions and excellent functional group compatibility. A variety of structurally interesting spiro-cyclopropanes were prepared in excellent yields and diastereomeric ratios (up to 97% yield and 20 : 1 dr). Also, ring expansion of the cyclopropanation product to quickly deliver a complex indeno[1,2-c]pyridazine structure showcased an interesting application of this method.