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Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
Author(s) -
Motsch Sebastian,
Schütz Christian,
Huy Peter H.
Publication year - 2018
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.201800907
Subject(s) - chemistry , nucleophile , sulfoxide , catalysis , benzoyl chloride , electrophile , lewis acids and bases , organic chemistry , reagent , formamide , nucleophilic substitution , combinatorial chemistry , medicinal chemistry
Herein, a method for the nucleophilic substitution (S N ) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol‐%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2‐methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side‐reaction also provided the explanation, why sulfoxide catalyzed S N ‐reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.