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Oxidative Coupling Reactions Mediated by MoCl 5 Leading to 2,2′‐Cyclolignans: The Specific Role of HCl
Author(s) -
Kramer Beate,
Fröhlich Roland,
Waldvogel Siegfried R.
Publication year - 2003
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/ejoc.200300263
Subject(s) - chemistry , oxidative addition , oxidative phosphorylation , aryl , oxidative coupling of methane , chloride , coupling reaction , organic chemistry , combinatorial chemistry , medicinal chemistry , catalysis , biochemistry , alkyl
The scope and performance of oxidative coupling reaction using MoCl 5 can be significantly improved by employing Lewis‐acidic additives such as TiCl 4 , SnCl 4 , or SiCl 4 . Since the by‐product, HCl, plays a particular function as an inhibitor for MoCl 5 by forming chloro complexes, exploiting typical chloride scavengers, like silver salts or molecular sieves, is also successful. A variety of differently substituted 1,4‐diarylbutanes 4a − g , which were easily synthesized by a modular approach, were subjected to the dehydrodimerization reaction. For the oxidative coupling reaction, a para ‐substitution pattern — with a donor group on the aryl system — is pivotal for allowing access to the 2,2′‐cyclolignans 5a , e − g . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)