Direct Catalytic Asymmetric Cyclopropylphosphonation Reactions of N,N-Dialkyl Groups of Aniline Derivatives by Ru(II)-Pheox Complex

Abstract

Novel catalysis involving phosphonomethylation of N-methylaniline and asymmetric cyclopropylphosphonation reactions of N,N-diethylaniline derivatives with diazomethylphosphonates are reported. Optically active cyclopropylphosphonate derivatives were directly synthesized from diazomethylphosphonates and N,N-diethylaniline derivatives catalyzed by a Ru(II)-Pheox complex in one step in good yields and high diastereoselectivities (up to trans/ cis = > 99:1<) and enantioselectivities (up to 99% ee). D-labeling mechanistic studies of phosphonomethylation and cyclopropylphosphonation suggested that an enamine or iminium intermediate was generated in the reaction process.

Catalytic Enantio- and Diastereoselective Cyclopropanation of 2-Azadienes for the Synthesis of Aminocyclopropanes Bearing Quaternary Carbon Stereogenic Centers

“…A straightforward way to prepare aminocyclopropanes is the enantio- and diastereoselective cyclopropanation of N -substituted olefins with disubstituted carbene precursors; , however, this strategy has seen limited success, being restricted to just a handful of examples. , Most cyclopropanations of N -alkenyl substrates have entailed reactions with ethyl diazoacetate or related α-diazoesters while also being constrained to terminal olefins, leading to products lacking quaternary carbons or more than two stereogenic centers . The expansion of this disconnection to encompass disubstituted olefins and/or donor/acceptor carbene precursors would provide access to more highly substituted cyclopropanes, including those bearing quaternary stereogenic centers.…”