Premium
Isolation of Azadiphosphiridines and Diphosphenimines by Cycloaddition of Azides and a Cationic Diphosphene
Author(s) -
Schwedtmann Kai,
Hennersdorf Felix,
Bauzá Antonio,
Frontera Antonio,
Fischer Roland,
Weigand Jan J.
Publication year - 2017
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/anie.201702058
Subject(s) - cycloaddition , chemistry , cationic polymerization , trifluoromethanesulfonate , medicinal chemistry , moiety , ring (chemistry) , stereochemistry , electrocyclic reaction , catalysis , organic chemistry , bicyclic molecule
The polarized, cationic diphosphene [( Cl Im Dipp )P=P(Dipp)] + as the triflate salt 7 [OTf]( Cl Im Dipp =4,5‐dichloro‐1,3‐bis(Dipp)‐imidazol‐2‐yl; Dipp=2,6‐diisopropylphenyl) reacts with azides of type RN 3 (R=Dipp or Dmp; Dmp=2,5‐dimethylphenyl) in a [2+3] cycloaddition reaction followed by the release of N 2 and a subsequent electrocyclic ring‐closing reaction to azadiphosphiridine salts [( Cl Im Dipp )P‐P(Dipp)‐N(R)] 10a,b [OTf] (R=Dipp or Dmp). The reaction of 7 [X] (X=OTf, GaCl 4 ) with the electron‐rich azides Me 3 SiN 3 and NaN 3 give the unusual diphosphenimine derivatives [( Cl Im Dipp )P−P(Dipp)=N(SiMe 3 )] + ( 11 [OTf]) and [( Cl Im Dipp )P−P(Dipp)=N(GaCl 3 )] ( 12 ), respectively, featuring an acyclic P 2 N moiety. Theoretical calculations provide insights into the reaction mechanisms to the cyclic and acyclic forms, in which the thermodynamic stability of the latter prevents the electrocyclic ring closure.