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Tin for Organic Synthesis, 11. A Mild and Effective Synthesis of α,β‐unsaturated Carboxamides and Sulfonamides by Electrophilic Substitution of Alkenylstannanes with Isocyanates
Author(s) -
Niestroj Michael,
Neumann Wilhelm P.,
Thies Olaf
Publication year - 1994
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19941270625
Subject(s) - chemistry , electrophilic substitution , tin , electrophile , substitution (logic) , substitution reaction , organic synthesis , electrophilic addition , organic chemistry , combinatorial chemistry , catalysis , computer science , programming language
A new and effective method for the preparation of a variety of olefinic carboxamides 6a–k and N ‐(4‐methylphenyl‐sulfonyl) carboxamides 7a–d is described. The reaction of aryl and alkyl isocyanates 4a–c or 4‐methylphenylsulfonyl isocyanate 5 with 1‐alkenyltrialkylstannanes 1a–e and di‐1‐alkenyldibutylstannanes 2a–c in the presence of aluminium trichloride provides the corresponding N ‐aryl‐substituted olefinic carboxamides 6a–k or the N ‐(4‐methylphenyl‐sulfonyl)‐substituted olefinic carboxamides 7a–d in good yields. The stannyl moiety is superior to hydrogen as a leaving group and enables electrophilic ipso substitution at the vinylic system. In the case of di‐1‐alkenyldibutylstannanes the substitutions are also stereospecific, whereas the reactions of 1‐alkenyltrialkylstannanes with isocyanates proceed with partial isomerisation.