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Title: Small Molecule Activation with Intramolecular “Inverse” Frustrated Lewis Pairs
Abstract

The intramolecular “inverse” frustrated Lewis pairs (FLPs) of general formula 1‐BR2‐2‐[(Me2N)2C=N]‐C6H4(36) [BR2=BMes2(3), BC12H8, (4), BBN (5), BBNO (6)] were synthesized and structurally characterized by multinuclear NMR spectroscopy and X‐ray analysis. These novel types of pre‐organized FLPs, featuring strongly basic guanidino units rigidly linked to weakly Lewis acidic boryl moieties via anortho‐phenylene linker, are capable of activating H−H, C−H, N−H, O−H, Si−H, B−H and C=O bonds.4and5deprotonated terminal alkynes and acetylene to form the zwitterionic borates 1‐(RC≡C‐BR2)‐2‐[(Me2N)2C=NH]‐C6H4(R=Ph, H) and reacted with ammonia, BnNH2and pyrrolidine, to generate the FLP adducts 1‐(R2HN→BR2)‐2‐[(Me2N)2C=NH]‐C6H4, where the N‐H functionality is activated by intramolecular H‐bond interactions. In addition,5was found to rapidly add across the double bond of H2CO, PhCHO and PhNCO to form cyclic zwitterionic guanidinium borates in excellent yields. Likewise,5is capable of cleaving H2, HBPin and PhSiH3to form various amino boranes. Collectively, the results demonstrate that these new types of intramolecular FLPs featuring weakly Lewis acidic boryl and strongly basic guanidino moieties are as potent as conventional intramolecular FLPs with strongly Lewis acidic units in activating small molecules.

 
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PAR ID:
10226750
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Chemistry – A European Journal
Volume:
27
Issue:
20
ISSN:
0947-6539
Page Range / eLocation ID:
p. 6263-6273
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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