Potassium tert-amylate ( t-AmylOK) is a well-known, commercially available base and generally regarded as a more solvent-soluble form of potassium tert-butoxide ( t-BuOK). However, despite the structural similarity between the tert-butyl and amyl moieties, potassium tert-amylate in toluene can undergo distinct physical property changes in the presence of protic solvents that warrant further consideration. This is particularly surprising given that t-AmylOH is a byproduct of deprotonation with t-AmylOK, as well as the fact that its structurally similar relative, t-BuOK, is commercially available in t-BuOH.
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http://dx.doi.org/10.1021/acs.joc.9b00815 | DOI Listing |
Chem Commun (Camb)
October 2019
Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria.
The new motif - α,α-difluoromethyl thioamide - has been assembled starting from isothiocyanate (as thioamide precursor) and a formal difluoromethyl-carbanion generated from commercially available TMSCHF2. Upon proper activation of this reagent with potassium tert-amylate, the high-yielding transfer of the difluorinated nucleophile takes place under high chemocontrol. Various sensitive functionalities (e.
View Article and Find Full Text PDFOrg Lett
October 2019
University of Vienna, Department of Pharmaceutical Chemistry , Althanstrasse, 14 , 1090 Vienna , Austria.
The homologation of Weinreb amides into difluoromethylketones with a formal nucleophilic CHF transfer agent is reported. Activating TMSCHF with potassium amylate enables a convenient access to the difluorinated homologation reagent, which adds to the acylating partners. The high chemoselectivity showcased in the presence of variously multifunctionalized Weinreb amides, jointly with uniformly high yields, enables the strategy of general applicability without requiring any stabilization element for the putative carbanion.
View Article and Find Full Text PDFJ Org Chem
June 2019
Research & Development , AbbVie Inc. , 1 N Waukegan Road , North Chicago , Illinois 60064 , United States.
Potassium tert-amylate ( t-AmylOK) is a well-known, commercially available base and generally regarded as a more solvent-soluble form of potassium tert-butoxide ( t-BuOK). However, despite the structural similarity between the tert-butyl and amyl moieties, potassium tert-amylate in toluene can undergo distinct physical property changes in the presence of protic solvents that warrant further consideration. This is particularly surprising given that t-AmylOH is a byproduct of deprotonation with t-AmylOK, as well as the fact that its structurally similar relative, t-BuOK, is commercially available in t-BuOH.
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