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Efficient Alkynylation of 2‐Oxindoles with Alkynyl Dibenzothiophenium Triflates: Total Synthesis of (±)‐Deoxyeseroline
Author(s) -
Roy Avishek,
Maity Arindam,
Giri Rahul,
Bisai Alakesh
Publication year - 2020
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202000027
Subject(s) - chemistry , moiety , alkynylation , electrophile , oxindole , alkyl , aryl , combinatorial chemistry , total synthesis , electrophilic substitution , organic chemistry , catalysis
We report here a highly efficient method for direct alkynylations of 3‐alkyl/aryl/indolyl 2‐oxindoles using a series of 5‐(alkynyl)dibenzothiophenium triflates ( 3 a – e ) under transition‐metal‐free conditions. This direct electrophilic alkynylation method gave access to a variety of 2‐oxindoles having quaternary center at the benzylic position in an operationally simple and inexpensive procedure. Further, chemoselective alkynylations could be realized in case of N−H free 2‐oxindoles and 3‐(indolyl)‐2‐oxindoles to afford a number of 3,3‐disubstituted‐2‐oxindoles. This methodology was then employed in the total synthesis of (±)‐deoxyeseroline ( 1 a ) as well as C(3a)‐indolyl furoindoline moiety ( 31 ).