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Metal‐Free Reagent Dependent SS and CC Homocoupling of α‐Enolic Dithioesters at Room Temperature: Direct Access to Fully Substituted Symmetrical Thiophenes via Chemoselective Paal–Knorr Approach
Author(s) -
Ramulu B. Janaki,
Nagaraju Anugula,
Chowdhury Sushobhan,
Koley Suvajit,
Singh Maya Shankar
Publication year - 2015
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.201400828
Subject(s) - chemistry , reagent , transition metal , metal , coupling reaction , sequence (biology) , coupling (piping) , combinatorial chemistry , organic chemistry , catalysis , metallurgy , biochemistry , materials science
An unprecedented metal‐free oxidative homodimerization of α‐enolic dithioesters has been achieved for the first time at room temperature within 5–10 min. Molecular iodine promotes the SS coupling leading to S , S ′‐bis(dithioacetals), while N ‐chlorosuccinimide facilitates CC coupling to give α,α′‐bis(β‐oxo dithioesters) in good to excellent yields. Furthermore, the newly generated α,α′‐bis(β‐oxo dithioesters) have been directly employed in the synthesis of fully substituted thiophenes with a unique symmetrical substitution pattern in a one‐pot, two‐step reaction sequence.