Palladium-Catalyzed Regio- and Enantioselective Hydrophosphination of gem-Difluoroallenes

Manganese(I)-Catalyzed Access to Enantioenriched Chiral Aziridine Phosphines

Herein, we present the first catalytic asymmetric nucleophilic addition of diarylphosphines to 2H-azirines, facilitated by a chiral Mn(I) complex. This method not only provides access to novel class of derivatives of the aziridine core - a structural motif recognized for its antitumor and antibacterial properties - but also introduces a phosphine moiety alongside the generation of an NH moiety within a strained three-membered ring. The discovery of this new Mn(I) complex that both enables the reaction and induces stereoselectivity is pivotal, as it underscores the significant potential of this earth-abundant metal in advancing asymmetric catalysis.

Diastereoselective and Enantioselective Hydrophosphinylations of Conjugated Enynes, Allenes and Dienes via Synergistic Pd/Co Catalysis

Different from the reported work focusing on the construction of single P- or C-stereocenter via hydrophosphinylation of unsaturated carbon bonds, the highly diastereo- and enantioselective hydrophosphinylation reaction of allenes, conjugated enynes and 1,3-dienes is achieved via a designed Pd/Co dual catalysis and newly modified masked phosphinylating reagent. A series of allyl motifs bearing both a tertiary C- and P-stereocenter are prepared in generally good yields, >20 : 1 dr, >20 : 1 rr and 99 % ee. The unprecedented diastereo- and enantioselective hydrophosphinylation of 1,3-enynes is established to generate skeletons containing both a P-stereocenter and a nonadjacent chiral axis. The first stereodivergent hydrophosphinylation reaction is also developed to achieve all four P-containing stereoisomers. The present protocol features the use of only 3-minutes reaction time and 0.1 % catalyst, and with the observation of up to 730 TON. A set of mechanistic studies reveal the necessity and roles of two metal catalysts and corroborate the designed synergistic process.

gem-Difluoroallene (DFA): an emerging versatile synthetic precursor to enable diverse fluorinated molecules

Organofluorine compounds are increasingly found in diverse fields, such as pharmaceuticals, agrochemicals, and materials science. gem-Difluoroallenes, which have gem-difluoro alkenes and allenes-like properties, offer a distinct and adaptable platform for novel synthetic transformations. Their distinctiveness is highlighted by various strategies, where the gem-difluoro group's presence plays a pivotal role in successful reactions. This review article presents a comprehensive overview of the latest progress in utilizing gem-difluoroallenes for selective additions, defluorination, as well as cycloaddition and cyclization reactions. We also discuss the limitations and future directions in this area, inspiring further exploration and innovation.

Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides via C-H activation and formal phosphoryl migration

A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized via cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields via the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity. Photophysical properties of selected 1,2-dihydrophosphete oxides are also disclosed.

Enantioselective Hydrophosphination of Terminal Alkenyl Aza-Heteroarenes

This paper presents a Mn(I)-catalysed methodology for the enantioselective hydrophosphination of terminal alkenyl aza-heteroarenes. The catalyst operates through H-P bond activation, enabling successful hydrophosphination of a diverse range of alkenyl-heteroarenes with high enantioselectivity. The presented protocol addresses the inherently low reactivity and the commonly encountered suboptimal enantioselectivities of these challenging substrates. As an important application we show that this method facilitates the synthesis of a non-symmetric tridentate P,N,P-containing ligand like structure in just two synthetic steps using a single catalytic system.

Copper-Catalyzed Protoarylation of gem-Difluoroallenes

A copper-catalyzed protoarylation of gem-difluoroallenes with aryl boronic esters has been developed, enabling highly regioselective synthesis of gem-difluoroalkenes in high yields. The mild reaction conditions allow for a variety of functional groups to be tolerated, and the reaction can be extended to protoalkenylation of gem-difluoroallenes. The synthetic utility of this method has been demonstrated in gram-scale operation as well as synthesis of chiral gem-difluoroalkenes bearing γ-carbon stereogenic centers in moderate enantioselectivity using a chiral bidentate phosphine ligand with a copper catalyst.

Z-Selective access to α-trifluoromethyl arylenes through Pd-catalysed fluoroarylation of 1,1-difluoroallenes

The synthesis of stereo-defined α-trifluoromethyl arylenes is of great importance in medical chemistry, organic chemistry, and materials science. However, despite the recent advances, the Z-selective formation of α-trifluoromethyl arylenes has remained underdeveloped. Here, we describe a facile approach towards Z-α-trifluoromethyl arylenes through Pd-catalysed stereoselective fluoroarylation of 1,1-difluoroallenes in the presence of a bulky monophosphine ligand.