Monobenzofused 1,4-azaborines: synthesis, characterization, and discovery of a unique coordination mode.
We report the first general synthesis of boron-substituted monobenzofused 1,4-azaborines using ring-closing metathesis of an enamine-containing diene as a key synthetic strategy. As part of our investigations, we discovered that the B-C3 moiety in a 1,4-azaborine can serve uniquely as a η(2)-L-type ligand. This functionality is exemplified by two κ(2)-N-η(2)-BC Pt complexes of a boron-pyridyl-substituted monobenzofused-1,4-azaborine. Single-crystal X-ray diffraction analysis of the Pt complexes shows a strong structural contribution from the iminium resonance form of the monobenzofused-1,4-azaborine ligand. We also demonstrate that a palladium(0) complex supported by a 1,4-azaborine-based phosphine ligand can catalyze hydroboration of 1-buten-3-yne with unique selectivity. In view of the importance of arene-metal π-interactions in catalytic applications, this work should open new opportunities for ligand design involving the 1,4-azaborine motif as an arene substitute.
Department of Chemistry, Boston College, Chestnut Hill, MA 02467 (USA).
Senmiao
S
Xu
Fredrik
F
Haeffner
Bo
B
Li
Lev N
LN
Zakharov
Shih-Yuan
SY
Liu
D001372:Aza Compounds / Q000737:chemistry*; D001895:Boron / Q000737:chemistry; D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D008968:Molecular Conformation; D010165:Palladium / Q000737:chemistry
D001372:Aza Compounds; D001896:Boron Compounds; D056831:Coordination Complexes; D008024:Ligands; D010165:Palladium; D001895:Boron
Azaborine; BN heterocycle; boron; coordination complex; phosphine