https://scholars.lib.ntu.edu.tw/handle/123456789/612095
Title: | Planar N-Heterocyclic Carbene Diarylborenium Ions: Synthesis by Cationic Borylation and Reactivity with Lewis Bases | Authors: | Farrell, Jeffrey M. Stephan, Douglas W. JEFFREY M. FARRELL |
Keywords: | boranes; borylation; carbenes; frustrated Lewis pairs; steric hindrance | Issue Date: | 2015 | Journal Volume: | 54 | Journal Issue: | 17 | Start page/Pages: | 5214-5217 | Source: | ANGEWANDTE CHEMIE-INTERNATIONAL EDITION | Abstract: | The NHC-borane adduct (IBn)BH3 (1) (NHC= N-heterocyclic carbene; IBn=1,3-dibenzylimidazol-2ylidene) reacts with [Ph3C][B(C6F5)4] through sequential hydride abstraction and dehydrogenative cationic borylation(s) to give singly or doubly ring closed NHC-borenium salts 2 and 3. The planar doubly ring closed product [C3H2(NCH2C6H4)2B][B(C6F5)4] is resistant to quaternization at boron by Et2O coordination, but forms classical Lewis acid-base adducts with the stronger donors Ph3P, Et3PO, or 1,4-diazabicyclo[2.2.2]octane (DABCO). Treatment of 3 with tBu3P selectively yields the unusual oligomeric borenium salt trans-[(C3H2(NCH2C6H4)2B)2(C3H2(NCHC6H4)2B)][B(C6F5)4] (7). Boron in action: Singly or doubly ring closed NHC-borenium salts (NHC= N-heterocyclic carbene) are prepared by dehydrogenative cationic borylation. Treatment of the planar doubly ring closed product (see picture, left) with tBu3P leads to the formation of an unusual trans C2-symmetric oligomeric borenium salt (right). Atom colors: C, black; N, blue; B, yellow. ? 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027928783&doi=10.1002%2fanie.201500198&partnerID=40&md5=2dfbdb811413c152b1c495b6eab1c87c https://scholars.lib.ntu.edu.tw/handle/123456789/612095 |
DOI: | 10.1002/anie.201500198 | SDG/Keyword: | Boron; Hydrides; Oligomers; Salts; Synthesis (chemical); boranes; Borylation; Carbenes; Frustrated lewis pairs; Steric hindrances; Organic compounds |
Appears in Collections: | 化學系 |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.