Advances in Catalytic Asymmetric Construction of Quaternary Stereogenic Centers by Conjugate Addition to β,β-Disubstituted Nitroalkenes

Quaternary stereogenic centers are of great importance because of their prevalence in a series of bioactive natural products and pharmaceuticals. Although the catalytic asymmetric construction of these highly congested centers poses a formidable challenge, this field has been extensively explored in the past few decades, and several elegant strategies, such as the asymmetric conjugate addition to β,β-disubstituted nitroalkenes, have been developed. The resultant β-nitro quaternary stereocenters can be conveniently transformed into the corresponding β-amino quaternary stereocenters commonly found in bioactive compounds. This review summarizes the recent advances in the construction of all-carbon quaternary or hetero-carbon quaternary stereocenters via metal-catalyzed and organocatalyzed asymmetric conjugate addition to β,β-disubstituted nitroalkenes, focusing on the scope, applications, and mechanisms of these reactions.