Catalytic Asymmetric Carbene Insertion Reactions into B-H Bonds Using a Ru(II)-Pheox Complex

The Ru(II)-Pheox catalyzed B-H bond insertion reactions of alpha-methyl diazoesters with phosphine- and amine-borane adducts were successfully developed. A unique alpha-methyl diazoester (dinaphthylenyl diazopropionate) with triphenylphosphine-borane afforded the highest enantioselectivity (up to 98 % ee). Moreover, a unique dinaphthylenyl diazophenylacetate was newly synthesized, leading to improved yield and enantioselectivity of the carbene transfer B-H insertion reaction.

Automated summary

The Ru(II)-Pheox catalyzed B-H bond insertion reactions of alpha-methyl diazoesters with phosphine- and amine-borane adducts were successfully developed. A unique alpha-methyl diazoester (dinaphthylenyl diazopropionate) showed the highest enantioselectivity, and a newly synthesized dinaphthylenyl diazophenylacetate led to improved yield and enantioselectivity of the carbene transfer B-H insertion reaction.