(Diborylmethyl)iodide

CAS 2831416-43-2, Cat. No EN300-46967415
C1 radical synthon

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(Diborylmethyl)iodide, or CHI(Bpin)₂, is a bench-stable α-iodo gem-diboryl reagent that functions as a versatile C1 radical synthon¹. The presence of two Bpin groups strongly stabilizes the adjacent carbon-centered radical, enabling controlled reactivity under mild catalytic conditions. In photocatalytic chemistry, CHI(Bpin)₂ is used as a radical cyclopropanation reagent for alkenes². Under visible-light photoredox catalysis (typically fac-Ir(ppy)₃ with CsF), it undergoes single-electron reduction to generate an α-diboryl radical, which adds to alkenes followed by polar cyclization to afford 1,2-substituted cyclopropyl boronic esters in good yields. The reaction shows high chemo- and diastereoselectivity and tolerates a wide range of functional groups, including halides, esters, amides, alcohols, heterocycles, and complex natural-product derivatives. Beyond alkenes, CHI(Bpin)₂ also participates in atom-transfer radical addition (ATRA) to alkynes under manganese catalysis and visible light, delivering γ-iodo-allylic gem-diboronates with high Z/E selectivity (up to ~96:4). These products are valuable synthetic linchpins, as the C–I bond and Bpin groups can be selectively transformed via cross-coupling, deborylation, oxidation, or homologation. In transition-metal catalysis, CHI(Bpin)₂ serves as an ambiphilic α-bimetalloid radical precursor in nickel-catalyzed C(sp³)–C(sp³) coupling reactions, such as ring-opening of cyclopropanols to give γ-carbonyl gem-diboronates³. This chemistry highlights the reagent’s ability to engage in radical–metal crossover pathways and further underscores the synthetic versatility of gem-diboryl motifs.

Synonyms: 2,2'-(iodomethylene)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane); 1,3,2-dioxaborolane, 2,2′-(iodomethylene)bis[4,4,5,5-tetramethyl- ; CHI(Bpin)₂; 2-[iodo(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)methyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane; (diborylmethyl)iodide