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Stoichiometric and Catalytic Inter‐ and Intramolecular Hydroamination of Terminal Alkynes by Frustrated Lewis Pairs
Author(s) -
Mahdi Tayseer,
Stephan Douglas W.
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501535
Subject(s) - hydroamination , frustrated lewis pair , chemistry , isoindoline , iminium , intramolecular force , borane , alkyne , pyrrolidine , lewis acids and bases , medicinal chemistry , steric effects , annulation , catalysis , aniline , stereochemistry , organic chemistry
Frustrated Lewis pairs (FLPs) based on sterically encumbered anilines and the Lewis acid B(C 6 F 5 ) 3 were found to react with terminal alkynes effecting intermolecular hydroamination affording iminium alkynylborate species of the form [RPhNC(R′)Me][R′CCB(C 6 F 5 ) 3 ]. In these cases, the reagent ratio of borane, aniline, and alkyne is 1:1:2. These reactions could also be performed in an intramolecular fashion by using anilines with alkynyl substituents effecting cyclization reactions. The use of 10 mol % B(C 6 F 5 ) 3 under a H 2 atmosphere provides a one‐pot synthesis of the pyrrolidine 12 , the piperidines 13 – 15 , the azepane 16 , the isoindoline 17 , and the benzoxazine 18 .