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Kinetically Controlled Protonation of a Cyclic Phosphamethanide Complex to a PH‐Phosphonium Ylide
Author(s) -
Ekici Sahir,
Gudat Dietrich,
Nieger Martin,
Nyulaszi Laszlo,
Niecke Edgar
Publication year - 2002
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/1521-3773(20020916)41:18<3367::aid-anie3367>3.0.co;2-7
Subject(s) - ylide , phosphonium , protonation , steric effects , chemistry , tetramethylethylenediamine , proton , crystallography , medicinal chemistry , photochemistry , stereochemistry , polymer chemistry , organic chemistry , ion , physics , quantum mechanics
The thermodynamically less favorable PH‐ylide 2 , not the corresponding phosphane, is formed in the kinetically controlled protonation of the cyclic phosphamethanide complex 1 . As the electrostatic potential on the surfaces of 1 shows, the attack of the proton on the sterically well shielded methanide carbon atom, and thus the formation of the phosphane form, is hindered. Consequently, a stable phosphonium ylide could be isolated for the first time in the condensed phase and characterized by X‐ray crystallography. R=SiMe 3 , tmeda= N , N , N ′, N ′‐tetramethylethylenediamine.