ABSTRACT Diarylhaloarsines (Ar 2 AsX; X = Cl, Br, I) are important intermediates in the synthesis of a wide range of organoarsenic compounds. However, previous methods have long been constrained by limited substrate scope and complex procedures. Herein, we report a practical and general synthetic approach for Ar 2 AsX from arsenic trioxide (As 2 O 3 ), an abundant and inexpensive arsenic source. The reaction of aryl Grignard reagents with As 2 O 3 affords diarylarsinous acids or diarsine oxides, depending on the steric demand of the aryl substituents. Subsequent halogenation with trimethylsilyl halides proceeds almost quantitatively under mild conditions to produce the corresponding Ar 2 AsX. The resulting Ar 2 AsX exhibit broad reactivity and can be used in the synthesis of BINAP‐type arsenic ligands, reductive formation of diarsines, and nickel‐catalyzed coupling reactions for direct aryl group incorporation. This method provides a convenient and scalable route to structurally diverse Ar 2 AsX and expands the applicability of these materials as versatile precursors for organoarsenic synthesis.
Sumida et al. (Fri,) studied this question.