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Bond‐Selective Nitrile Insertion into the 2 H ‐Azaphosphirene Ring System as Induced by Tetracyanoethylene
Author(s) -
Streubel Rainer,
Wilkens Hendrik,
Jones Peter G.
Publication year - 2000
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(20001103)6:21<3997::aid-chem3997>3.0.co;2-w
Subject(s) - tetracyanoethylene , chemistry , acetonitrile , metal , toluene , medicinal chemistry , solvent , crystallography , stereochemistry , organic chemistry
Competitive reactions of 2 H ‐azaphosphirene metal complexes 1 a – c (M=Cr, Mo, W) with 1‐piperidinonitrile and tetracyanoethylene in toluene have been observed at elevated temperatures. For the case of complex 1 c , the Δ 5 ‐1,2‐azaphospholene complex 2 c (as main product) and the 2 H ‐1,4,2‐diazaphosphole complex 3 c (as by‐product) were separated from the product mixture. At ambient temperature and using 1‐piperidinonitrile as solvent, bond and regioselective insertion of 1‐piperidinonitrile into the P−N bond of 2 H ‐azaphosphirene metal complexes 1 a – c (M=Cr, Mo, W) has been achieved in the presence of tetracyanoethylene (TCNE), yielding 2 H ‐1,4,2‐diazaphosphole metal complexes 3 a – c ; analogous reactions in benzo‐ or acetonitrile afforded the 2 H ‐1,4,2‐diazaphosphole tungsten complexes 3 d , e . A preliminary study with the 2 H ‐azaphosphirene tungsten complex 1 c and 1‐piperidinonitrile as solvent has revealed that substoichiometric amounts of TCNE (0.3 equiv) induce approximately 70 % conversion of complex 1 c . NMR data of the complexes 2 c and 3 a – e and the X‐ray structure of complex 3 c are discussed.