159888-30-9Relevant academic research and scientific papers
Atropisomeric amides as chiral, ligands: Using (-)-sparteine-directed enantioselective silylation to control the conformation of a stereogenic axis
Clayden,Johnson,Pink,Helliwell
, p. 7033 - 7040 (2007/10/03)
An enantiomerically pure (1-trimethylsilyl)ethyl group, constructed by a (-)-sparteine-directed enantioselective quench of a laterally lithiated tertiary aromatic amide, exerts powerful thermo-dynamic control over the conformation of the adjacent tertiary amide substituent. Ortholithiation and functionalization of the amide in the 6-position allows the single amide conformer to be trapped as an enantiomerically and diastereoisomerically pure amide atropisomer. Protodesilylation of the amide gives functionalized atropisomeric amides with a stereogenic axis of single absolute configuration, whose barriers to racemization have been determined by polarimetry. Enantiomerically pure amides bearing phosphine substituents are effective ligands in a Pal-catalyzed allylic substitution reaction - the first use of a nonbiaryl atropisomer as a chiral ligand - and give products with 90% ee. The rate of racemization of the phosphine-substituted amide is powerfully influenced by the presence of palladium.
Conformationally interlocked amides: Remote asymmetric induction by mechanical transfer of stereochemical information
Clayden, Jonathan,Pink, Jennifer H.,Yasin, Samreen A.
, p. 105 - 108 (2007/10/03)
The axial conformation of an aromatic tertiary amide group may be powerfully influenced by an adjacent stereogenic centre. Because the amide axis can also control the formation of new chiral centres, the amide can act as a 'relay centre' for the transmiss
