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Palladium‐Catalyzed Migratory Insertion of Isocyanides into C(thiophene)–SMe Bonds: Access to Atom‐Transfer Reactions
Author(s) -
Vahabi Amir Hossein,
Alizadeh Abdolali,
Khavasi Hamid Reza,
Bazgir Ayoob
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.201701026
Subject(s) - chemistry , isocyanide , catalysis , palladium , migratory insertion , reductive elimination , combinatorial chemistry , thiophene , medicinal chemistry , atom economy , transition metal , stereochemistry , organic chemistry
Pd II ‐catalyzed CN‐directed addition of isocyanides to C(sp 2 )–SMe bonds of thiophenes (generated in situ) effectively recycles the SMe activating group into thioimidate products. The catalytic sequence includes selective C(sp 2 )–SMe bond activation/migratory insertion of isocyanides into C(sp 2 )–Pd IV and subsequent C(sp 2 )–SMe bond‐forming reductive elimination from imidoyl–Pd IV –SMe complexes. Through these transition‐metal‐catalyzed addition reactions we have established isocyanides as a new template for atom‐transfer reactions. This groundbreaking research avoids the use of ancillary ligands that is a constant feature of all previously reported addition reactions with C–S bonds. This process proceeds through a high‐valent Pd II/IV catalytic cycle, which – to the best of our knowledge – has not been previously reported in this regard. Isocyanide insertion into C(Ar)–S bonds through addition is also unprecedented. Finally, the resulting thioimidates were demonstrated to be convenient precursors for the synthesis of thieno[2,3‐ c ]pyrroles by targeting the recycled SMe group for the second time in a cascade reaction process.