Cross-benzoin condensation mechanisms

A review of the asymmetric Stetter and asymmetric benzoin reactions focuses mainly on two classes of highly successful catalysts NHCs and metallophosphites. A new NHC, pyrido[l,2-a]-2-ethyl[l,2,4]triazol-3-ylidene (99), is a powerful catalyst of benzoin condensation in the presence of potassium f-butoxide. A DFT study of the mechanism suggests that the f-butanol solvent is explicitly involved. o-Phthalaldehyde chalcones (100) undergo intramolecular aldehyde-ketone crossed-benzoin condensation to naphthalenone tertiary alcohols (101) in yields up to 94%, in 20 min, using NHC catalysis. ... 

Lapworth, A. J. J. Chem. Soc. 1903, 83, 995. Arthur Lapworth (1872—1941) was bom in Scotland. He was one of the great figures in the development of the modem view of the mechanism of organic reactions. Lapworth investigated the Benzoin condensation at the Chemical Department, The Goldsmiths Institute, New Cross, UK. 

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