asymmetric cycloaddition, a nitrogen-nitrogen double bond has never been investigated in chiral phosphine catalysis. In this paper, we present phosphine-catalyzed asymmetric [3+2] cycloaddition of diazenes with Morita-Baylis-Hillman (MBH) carbonates to give chiral dihydropyrazoles in high yields with excellent enantioselectivities. Various MBH carbonates and diazenes worked well under the mild reaction conditions
We report the first asymmetric synthesis of P-stereogenic phosphanyl hydrazines via nickel-catalyzed asymmetric addition of primary phosphines to azo compounds. We anticipate that the remarkable versatility of these P-stereogenicsecondaryaminophosphines will facilitate the facile synthesis of both previously known and novelP-stereogenic compounds.