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Addition of a Phosphinidene Complex to C=N Bonds: P‐Ylides, Azaphosphiridines, and 1,3‐Dipolar Cycloadditions
Author(s) -
Vlaar Mark J. M.,
Valkier Pieter,
de Kanter Frans J. J.,
Schakel Marius,
Ehlers Andreas W.,
Spek Anthony L.,
Lutz Martin,
Lammertsma Koop
Publication year - 2001
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 - 10.1002/1521-3765(20010817)7:16<3551::aid-chem3551>3.0.co;2-m
Subject(s) - phosphinidene , chemistry , imine , ring (chemistry) , cycloaddition , intramolecular force , adduct , stereochemistry , medicinal chemistry , diimine , crystallography , catalysis , organic chemistry
The terminal phosphinidene complex PhPW(CO) 5 adds to the imine bond of PhHC=N−Ph to give 3‐membered ring azaphosphiridines, which undergo ring‐expansion with an additional imine to yield a set of four isomeric five‐membered ring diazaphospholanes. Treatment with the diimines PhHC=N‐(CH 2 ) n ‐N=CHPh ( n =2,3,4) results instead—in all three cases—in only a single isomer of the (CH 2 ) n bridged diazaphospholane. For n =2 or 3, this aminal group is easily hydrolyzed to afford new 6‐ and 7‐membered ring heterocycles. No intermediate azaphosphiridine complex is observed during the addition reaction to the diimines. B3LYP/6–31G* calculations on an unsubstituted, uncomplexed system suggest that the initially formed P,N‐ylide of the H 2 C=N‐(CH) 2 ‐N=CH 2 diimine both kinetically and thermodynamically favors an intramolecular 1,3‐dipolar cycloaddition over an imine insertion into the CPN ring of an intermediate azaphosphiridine. Single‐crystal X‐ray structures for the (CH 2 ) 2 ‐bridged azaphospholane complex and the HCl adduct of the 7‐membered hydrolysis product are presented.