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Observation of a Thermally Induced Bora‐Nazarov Cyclization at a Phosphole Framework
Author(s) -
Möbus Juri,
Kehr Gerald,
Daniliuc Constantin G.,
MückLichtenfeld Christian,
Erker Gerhard
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201502850
Subject(s) - borane , phosphole , chemistry , steric effects , electrophile , reagent , nuclear magnetic resonance spectroscopy , medicinal chemistry , crystallography , stereochemistry , computational chemistry , catalysis , organic chemistry
The reaction of the bis(enynyl)phosphanes 6 a , b with the electrophilic borane reagents RB(C 6 F 5 ) 2 (R=C 6 F 5 , CH 2 CH 2 Ph, CH 3 ) gave phospholes cleanly in a 1,1‐carboboration reaction sequence. Depending on the steric bulk, the resulting 2,5‐alkenylphospholes underwent a thermally induced bora‐Nazarov type cyclization. The equilibrium situation of these examples of a bora‐Nazarov type cyclization was investigated in detail by NMR spectroscopy, X‐ray crystal structure analysis, and DFT calculations.