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Atropisomerism in Diarylamines: Structural Requirements and Mechanisms of Conformational Interconversion
Author(s) -
Costil Romain,
Sterling Alistair J.,
Duarte Fernanda,
Clayden Jonathan
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202007595
Subject(s) - atropisomer , chemistry , steric effects , axial chirality , chirality (physics) , stereochemistry , substituent , computational chemistry , enantioselective synthesis , organic chemistry , catalysis , nambu–jona lasinio model , chiral symmetry breaking , physics , quantum mechanics , quark
Abstract In common with other hindered structures containing two aromatic rings linked by a short tether, diarylamines may exhibit atropisomerism (chirality due to restricted rotation). Previous examples have principally been tertiary amines, especially those with cyclic scaffolds. Little is known of the structural requirement for atropisomerism in structurally simpler secondary and acyclic diarylamines. In this paper we describe a systematic study of a series of acyclic secondary diarylamines, and we quantify the degree of steric hindrance in the ortho positions that is required for atropisomerism to result. Through a detailed experimental and computational analysis, the role of each ortho ‐substituent on the mechanism and rate of conformational interconversion is rationalised. We also present a simple predictive model for the design of configurationally stable secondary diarylamines.