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Adduct Formation, B−H Activation and Ring Expansion at Room Temperature from Reactions of HBcat with NHCs
Author(s) -
WürtembergerPietsch Sabrina,
Schneider Heidi,
Marder Todd B.,
Radius Udo
Publication year - 2016
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/chem.201603328
Subject(s) - adduct , ring (chemistry) , chemistry , organic chemistry
We report the reactions of catecholborane (HBcat; 1 ) with unsaturated and saturated NHCs as well as CAAC Me . Mono‐NHC adducts of the type HBcat⋅NHC (NHC= n Pr 2 Im, i Pr 2 Im, i Pr 2 Im Me , and Dipp 2 Im) were obtained by stoichiometric reactions of HBcat with the unsaturated NHCs. The reaction of CAAC Me with HBcat yielded the B−H activated product CAAC Me (H)Bcat via insertion of the carbine‐carbon atom into the B−H bond. The saturated NHC Dipp 2 SIm reacted in a 2:2 ratio yielding an NHC ring‐expanded product at room temperature forming a six‐membered −B−C=N−C=C−N− ring via C−N bond cleavage and further migration of the hydrides from two HBcat molecules to the former carbene‐carbon atom.