Use of organoboron halides in organic synthesis

Abstract

Several new organic transformations have been achieved utilizing boron halide reagents. Aryl aldehydes are conveniently converted to gem-dichloromethylbenzenes using boron trichloride. Aryl aldehydes are alkylated by alkylboron chlorides in a Grignard-like fashion to generate the corresponding arylalkanols or alkylboron chlorides. Aryl aldehydes react with divinylboron halides (generated via the haloboration of alkynes) to produce 1,5-dihalo-1,4-dienes in excellent yields.

Electrocatalytic synthesis of α,α-gem-dihalide ketones from α-mono-halide ketones and unexpected dimer condensation

“…Interestingly, fluorination could be achieved using this method. When using NaF as the fluorine source, α-halide-α-fluoroproducts were prepared in yields of 60-70% (22)(23)(24)(25)(26)(27). Using this method, quaternary carbon gem-dihalides with diverse substituents such as cyclic rings (28, 79%) and phenyl groups (29, 81%, and 30, 78%) were also obtained in good yields.…”

“…Initially, α-halide-α-alkoxy epoxides derived from alcohols were used to form gem -dihalide alkoxide products via solvolysis. 22 Later, halogenation methods, such as two-phase diazotization/halogenation, 2,23 boron trichloride 24 or dihalocarbene 25 methods, and nitrile/amide bio-transformations 26,27 were reported. N -halo succinimides (NXS) were also used for selective gem -dihalogenation.…”