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Tandem Chemoselective 1,2‐/1,4‐Migration of the Thio Group in Keto Thioesters: An Efficient Approach to Substituted Butenolides
Author(s) -
Mal Kanchan,
Naskar Sandip,
Sen Shovan Kumar,
Natarajan Ramalingam,
Das Indrajit
Publication year - 2016
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201600640
Subject(s) - chemistry , thio , tandem , phosphonate , carbanion , reagent , thioester , combinatorial chemistry , stereochemistry , sulfur , medicinal chemistry , organic chemistry , enzyme , materials science , composite material
We report herein an efficient and mechanistically unique tandem chemoselective 1,2‐/1,4‐migration of the thio group in keto thioesters that provides substituted butenolides in moderate to excellent yields. Thus, α‐keto thioesters in the presence of stabilized phosphonate carbanions undergo tandem 1,2‐sulfur migration; whereas 1,4‐migration of the thio group has been achieved with the same thioesters after the treatment with Wittig reagents followed by BF 3 ⋅OEt 2 ‐catalyzed tandem reaction. The crossover experiments and the isolation of intermediates reveal a stepwise mechanism for both of these transformations.