title: Cinchonidinium acetate as a convenient catalyst for the asymmetric synthesis ofcis-stilbenediamines.
abstract: Inexpensive and readily available cinchonidinium acetate is an effective catalyst for thesyn-selectiveaza-Henry reaction of arylnitromethanes and aryl imines. The resulting maskedcis-stilbenediamine products are produced in excellent diastereoselectivity and good enantioselectivity, and enantiopure material can be achieved via recrystallization. The features of thecinchonacatalyst needed for selectivity are discussed, with specific emphasis on formation of a kinetically controlledsyn-product without epimerization of the highly acidicα-nitro stereocenter.
authors.affiliation: Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, PA 19104, United States.
authors.forename: Ryan R
authors.initials: RR
authors.lastname: Walvoord
authors.affiliation: Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, PA 19104, United States.
authors.forename: Marisa C
authors.initials: MC
authors.lastname: Kozlowski
keywords: Asymmetric organocatalysis; Aza-Henry; Cinchona alkaloid; Nitro-Mannich; Vicinal diamine