Details

Autor(en) / Beteiligte

• Yamamoto, Kensuke
• Mohara, Yusei
• Mutoh, Yuichiro
• Saito, Shinichi

Titel

Ruthenium-Catalyzed (Z)‑Selective Hydroboration of Terminal Alkynes with Naphthalene-1,8-diaminatoborane

Ist Teil von

• Journal of the American Chemical Society, 2019-10, Vol.141 (43), p.17042-17047

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The metal-catalyzed (Z)-selective hydroboration of terminal alkynes is synthetically challenging due to the usually (E)-selective nature of the hydroboration and the formation of the thermodynamically unstable (Z)-isomer. Herein, we report that N-heterocyclic-carbene-ligated ruthenium complexes catalyze the (Z)-selective hydroboration of terminal alkynes with H–B­(dan) (dan = naphthalene-1,8-diaminato), which generates a diverse range of synthetically valuable (Z)-alkenylboranes. Mechanistic studies, particularly the isolation of a catalytically relevant borylruthenium complex, revealed a mechanism that involves the insertion of the alkyne into a Ru–B bond, which provides a catalytic cycle that is distinctly different from that of previously reported (Z)-selective hydroborations. The direct cross-coupling of the obtained (Z)-alkenyl-B­(dan) enables the rapid synthesis of biologically active Combretastatin A-4 analogues.