Tertiary Pentyl Groups Enhance Salen Titanium Catalyst for Highly Enantioselective Trimethylsilylcyanation of Aldehydes

• Published in: Journal of organic chemistry Vol. 67; no. 8; pp. 2702 - 2704
• Main Authors: Liang, Sidney, Bu, Xiu R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 19-04-2002
• Subjects: Acetonitriles - chemistry; Aldehydes - chemistry; Catalysis; Catalysts: preparations and properties; Chemistry; Ethylenediamines - chemistry; Exact sciences and technology; General and physical chemistry; Magnetic Resonance Spectroscopy; Molecular Structure; Pentanes - chemistry; Silicon Compounds - chemistry; Stereoisomerism; Structure-Activity Relationship; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titanium - chemistry; Catalytic reaction; Transition element complexes; Nitrile; Enantioselectivity; Silylation; Titanium complex; Benzaldehyde; Organic ligand; Temperature effect; Alcohol; Organic silane; Aldehyde; Schiff base; Asymmetric synthesis; Steric effect; Aromatic compound; Cyaniding; Chemical synthesis
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo0161779

tert-Pentyl groups are recognized to be highly effective steric groups that can enhance enantioselectivity of salen titanium complexes when they are used in asymmetrical cyanation of aromatic aldehydes. High ee (92−97%) has been obtained with several aldehyde substrates. Compared to its tert-butyl analogue, the tert-pentyl group has been found to improve enantioselectivity and in some cases quite dramatically.