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Facile Reduction of Aromatic Aldehydes, Ketones, Diketones and Oxo Aldehydes to Alcohols by an Aqueous TiCl 3 /NH 3 System: Selectivity and Scope
Author(s) -
Clerici Angelo,
Pastori Nadia,
Porta Ombretta
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200210)2002:19<3326::aid-ejoc3326>3.0.co;2-v
Subject(s) - chemistry , chemoselectivity , aqueous solution , methanol , aldehyde , organic chemistry , selectivity , ketone , combinatorial chemistry , catalysis
A simple and rapid procedure for the almost quantitative reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by use of TiCl 3 /NH 3 in aqueous methanol solution is reported. The reducing system distinguishes between different classes of aldehydes and/or ketones, and many functionalities that usually do not survive under reducing conditions are tolerated well. The concept of reversal of chemoselectivity has also been developed. A mechanism based on two sequential one‐electron transfers from Ti III to the carbonyl carbon atom is proposed, the second SET becoming operative only in the presence of ammonium ion (either added or formed in situ). (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)