An Organocatalyst Bearing Stereogenic Carbon and Sulfur Centers as an Efficient Promoter for Enantioselective Hydrosilylation of 1,4-Benzooxazines
摘要:
The efficient and enantioselective hydrosilylation of 3-aryl-1,4-benzooxazines was achieved using an l-phenyl alanine derived new Lewis base catalyst bearing stereogenic carbon and sulfur centers. In the presence of 2 mol % of catalyst, a broad range of 3-aryl-1,4-benzooxazines were hydrosilylated to afford the corresponding chiral 3-aryl-3,4-dihydro-2H-1,4-benzooxazine products with good to high yields (66-98%) and enantioselectivities (70-99% ee). This method provides an alternative approach with great practical application potential to access chiral 3-aryl-3,4-dihydro-2H-1,4-benzooxazines.
Ir-Catalyzed Enantioselective Hydrogenation of 2<i>H</i>-1,4-Benzoxazines with a Chiral 1,2,3,4-Tetrahydro-1-naphthylamine Derived Phosphine-aminophosphine Ligand
作者:Juan Hu、Daoyong Wang、Zhuo Zheng、Xiangping Hu
DOI:10.1002/cjoc.201200944
日期:2012.11
Unsymmetrical hybrid chiral phosphine‐aminophosphine ligandderived from 1,2,3,4‐tetrahydro‐1‐naphthylamine has been found to be highly efficient in the Ir‐catalyzed asymmetric hydrogenation of various 3‐aryl‐2H‐1,4‐benzoxazines, providing good enantioselectivities (up to 95% ee) and high catalytic activity (S/C up to 5000).
已发现衍生自1,2,3,4-四氢-1-萘胺的不对称杂化手性膦-氨基膦配体在各种3-芳基-2 H -1,4-苯并恶嗪的Ir催化不对称氢化中非常有效,提供良好的对映选择性(高达95%ee)和高催化活性(S / C高达5000)。