Monofluoroalkanes are important in many pharmaceuticals, agrochemicals and functional materials. However, the lack of easily available and transformable monofluoroalkylating reagents that facilitate a broad array of transformations has hampered the application of monofluoroalkylation. Herein, we report a general and efficient method of preparing diverse aliphatic monofluorides with monofluoroalkyl triflate as the synthetic scaffold. Using both nickel-catalyzed hydromonofluoroalkylation of unactivated alkenes and copper-catalyzed CÀ C bond formation, the general diversification of the monofluoroalkylating scaffold has been exhibited. The broad utility of this monofluoroalkylating reagent is shown by concise conversion into various conventional fluoroalkylating reagents and construction of monofluoro-alkoxy, -alkylamino motifs with commercially available heteroatom-based coupling partners.
Fluorinated motifs are frequently
encountered in drugs and agrochemicals.
Incorporating fluorine-containing motifs in drug candidates for lead
optimization in pharmaceutical research and development has emerged
as a powerful tool. The construction of molecules that feature a trifluoromethyl
(CF3−) group on a stereogenic carbon has accumulated
broad research efforts. Unlike its well-explored, biologically active
methyl counterpart, asymmetric construction of β-trifluoromethylated
alcohols bearing adjacent stereocenters still remains elusive. Through
retrosynthetic analysis, we posited that followed by sequential reduction
of carbonyl, the initial construction of chiral α-trifluoromethylated
ketones could render the desired product in a facile, one-pot fashion.
Herein, we developed the first example of nickel-catalyzed asymmtric
reductive cross-coupling trifluoroalkylation of acyl chlorides for
enantioselective synthesis of diverse α-trifluoromethylated
ketones. The one-pot reduction of these α-trifluoromethylated
ketones furnished corresponding alcohols bearing β-CF3-substituted stereogenic carbons with excellent diastereoselectivity
and complete enantioselective retention. High yields/enantioselectivity,
mild conditions, and good functional group compatibility are shown
in the system. Utilities of the method are also illustrated by applying
asymmetric, late-stage trifluoroalkylation of biologically active
complex molecules, revealing tremendous potential for development
of CF3-containing chiral drugs.
A photoinduced copper-catalyzed strategy for the monofluoroalkylation of alkynes with readily available monofluoroalkyl triflates was developed. It provides a new protocol to access valuable propargyl fluoride compounds via C−C bond formation by avoiding the use of highly toxic fluorination reagents. This reaction proceeded under mild conditions to afford propargyl monofluorides in moderate to high yields. Preliminary mechanistic studies reveal that a ligand-matched alkynyl copper complex might be the key photoactive substance.
Monofluoroalkanes are important in many pharmaceuticals, agrochemicals and functional materials. However, the lack of easily available and transformable monofluoroalkylating reagents that facilitate a broad array of transformations has hampered the application of monofluoroalkylation. Herein, we report a general and efficient method of preparing diverse aliphatic monofluorides with monofluoroalkyl triflate as the synthetic scaffold. Using both nickel-catalyzed hydromonofluoroalkylation of unactivated alkenes and copper-catalyzed CÀ C bond formation, the general diversification of the monofluoroalkylating scaffold has been exhibited. The broad utility of this monofluoroalkylating reagent is shown by concise conversion into various conventional fluoroalkylating reagents and construction of monofluoro-alkoxy, -alkylamino motifs with commercially available heteroatom-based coupling partners.
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