N-Fluorobenzenesulfonimide is a mild electrophilic fluorinating reagent, that can also be used as a strong oxidant for the promotion of reductive elimination from transition metals.
Orangoselenium catalysis enables an efficient route to 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of a base. In the absence of bases α,β-unsaturated aldehydes were formed in excellent yield. The hydroxy group is crucial for the direct amination.
Z. Deng, J. Wei, L. Liao, H. Huang, X. Zhao, Org. Lett., 2015, 17, 1834-1837.
A highly diastereoselective Pd-catalyzed carbonyl allylation of aldehydes and isatins with simple acyclic olefins as allylating reagents consists of a Pd-catalyzed oxidative allylic C-H borylation and an allylboration of carbonyls accelerated by phosphoric acid. N-Fluorobenzenesulfonimide as oxidant plays a key role.
Z.-L. Tao, X.-H. Li, Z.-Y. Han, L.-Z. Gong, J. Am. Chem. Soc., 2015, 137, 4054-4057.
A new selenium-catalyzed protocol for the direct, intramolecular amination of C(sp2)-H bonds of ortho-vinyl anilines and vinylated aminopyridines using N-fluorobenzenesulfonimide as the terminal oxidant enables the facile formation of a broad range of diversely functionalized indoles and azaindoles, respectively. Key factor is the pronounced carbophilicity of selenium electrophiles for the catalytic activation of alkenes.
S. Ortgies, A. Breder, Org. Lett., 2015, 17, 2748-2751.
A catalytic asymmetric coupling of aryl alkyl ketenes with commercially available N-fluorodibenzenesulfonimide (NFSI) and C6F5ONa furnishes tertiary α-fluoroesters. Mechanistic studies suggest that the addition of an external nucleophile (C6F5ONa) is critical for turnover, releasing the catalyst from an N-acylated intermediate.
S. Y. Lee, S. Neufeind, G. C. Fu, J. Am. Chem. Soc., 2014, 136, 8899-8902.
Functionalized aryl- or heteroarylmagnesium reagents, prepared from the corresponding bromides or iodides using halogen-magnesium exchange or direct magnesium insertion in the presence of lithium chloride, reacted smoothly with N-fluorobenzenesulfonimide to give the corresponding aromatic fluorides in good yields.
S. Yamada, P. Knochel, Synthesis, 2010, 2490-2494.
A transition-metal-free coupling of esters with geminal bis(boron) compounds provides an α,α-bis(enolate) equivalent which can be trapped with electrophiles including alkyl halides and fluorinating agents. This presents an efficient, convergent synthetic strategy for the synthesis of α,α-difunctionalized ketones.
C. E. Iacono, T. C. Stephens, T. S. Rajan, G. Pattison, J. Am. Chem. Soc., 2018, 140, 2036-2040.
With a suitable combination of N-heterocyclic carbene precatalyst, base, and fluorine reagent, a fluorination of alkynals proceeded smoothly to yield a wide range of α-fluoroallenoates with excellent chemoselectivity. α-Fluorinated allenoates are versatile synthetic intermediates toward other useful fluorine-containing building blocks.
X. Wang, Z. Wu, J. Wang, Org. Lett., 2016, 18, 576-579.
An organocatalytic system of L-proline and salicylic acid enables a highly stereoselective synthesis of α,α-difluoro-γ,γ-disubstituted butenals. The reaction offers a wide substrate scope and excellent E stereoselectivity in most cases.
S. Arimitsu, M. Nakasone, J. Org. Chem., 2016, 81, 6707-6713.