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Towards the Iodine‐Catalyzed Regioselective Sulfenylation of Unsymmetrical Ketones
Author(s) -
Devi Namita,
Rahaman Rajjakfur,
Sarma Kuladip,
Khan Tuhina,
Barman Pranjit
Publication year - 2017
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.201601562
Subject(s) - chemistry , reagent , iodine , lewis acids and bases , regioselectivity , catalysis , yield (engineering) , solvent , organic chemistry , base (topology) , potassium , lewis acid catalysis , reaction conditions , combinatorial chemistry , mathematical analysis , materials science , mathematics , metallurgy
An efficient method for the synthesis of β‐keto sulfides was developed. A thermodynamically stable enolate was generated from unsymmetrical ketones and was found to react with sulfenyl iodides generated in situ from various disulfides to give α‐sulfenylation products. Potassium tert ‐butoxide was used in a solvent mixture of t BuOH/1,3‐dimethyl‐2‐imidazolidinone (DMI, 7:3) at a mild reaction temperature of 40 °C. This iodine‐catalyzed method led to products in excellent yields up to 92 % within 2 h. The method is economical and no hazardous waste products are recovered throughout the process. The protocol is important, as unmodified ketones (linear and cyclic) are easily sulfenylated, which is otherwise not trivial. The Lewis acid FeCl 3 could be used as an alternative reagent to avoid the use of base and DMI. However, treatment with this Lewis acid lowered the yields and the maximum yield obtained was 85 %.