Asymmetric Ir-catalyzed hydrogenation of 4-R-1,3-dihydro-2H-1,5-benzodiazepin-2-ones using a novel phosphoramidite ligand

Abstract

A novel chiral phosphoramidite ligand, (S_a)-2-[N-ethyl-N-(1-naphthylmethyl)amino]-dinaphtho[2,1-d:1´,2´-f][1,3,2]dioxaphosphepane, was obtained and tested in Ir-catalyzed asymmetric hydrogenation of a series of 4-R-1,3-dihydro-2H-1,5-benzodiazepin-2-ones, wherein up to 74% ee was achieved. The structure of the resulting compounds was determined based on one- and two-dimensional NMR (¹H, ¹³C, ³¹P, ¹H—¹H COSY, ¹H—¹H ROESY, ¹H—¹³C HSQC and ¹H—¹³C HMBC) spectroscopy data.