Catalytic asymmetric construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements

An organocatalytic asymmetric process was reported for the sterically precise construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements. A series of interesting products featuring the union of a centrally chiral pyrazolone moiety and an axially chiral styrene unit were obtained in high yield with excellent diastereoselectivity and enantioselectivity (up to 99% ee, >20 : 1 dr). The process has the characteristics of mild reaction conditions, simple operation and broad substrate scope. The result of gram-scale reaction indicates that the reaction has good practicability.

Automated summary

An organocatalytic asymmetric process was reported for the construction of C-4 alkenyl substituted pyrazolone derivatives bearing multiple stereoelements with high yield and excellent diastereoselectivity and enantioselectivity. The process features mild reaction conditions, simple operation, broad substrate scope, and good practicability as demonstrated by gram-scale reactions.