Activation of vinylic carbon–chlorine bond by nickel complexes supported with phosphine ligands

• Activation of the vinylic C–Cl bond.
• Nickel complexes supported by trimethylphosphine ligands.
• β-Chlorinated vinylic aldehyde.
• β-Chlorinated cycloalkenyl acetals.

The vinylic C–Cl bonds of ortho-chlorinated cycloalkenyl aldehydes (1–4) and ortho-chlorinated cycloalkenyl acetal derivatives (5–6) were successfully activated by nickel(0) and nickel(II) complexes supported by trimethylphosphine ligands. Except one trans-five-coordinate nickel(II) chloride complex trans-[Ni(PMe3)2Cl{(C5H6)CHO}] (7) as a cyclometalation product with coordination of the aldehyde group, the other six four-coordinate nickel(II) chloride complexes trans-[Ni(PMe3)2Cl{(C5H6)CHO}] (8), trans-[Ni(PMe3)2Cl{(C6H8)CHO}] (9), trans-[Ni(PMe3)2Cl{(C6H7Memeta)CHO}] (10), trans-[Ni(PMe3)2Cl{(C6H7Bu-tmeta)CHO}] (11), trans-[Ni(PMe3)2Cl{(C6H8)CH(OCH2CH2O)}] (12) and trans-[Ni(PMe3)2Cl{(C6H7Bu-t-meta)CH(OCH2CH2O)}] (13) as C–Cl bond activation products were obtained without coordination of the aldehyde groups. These complexes were characterized by IR and NMR. The crystal and molecular structures of complexes 8, 9 and 12 were determined by single crystal X-ray diffraction.

Seven nickel(II) chlorides 7–13 as activation products of the vinylic C–Cl bond were successfully synthesized. The molecular structures of complexes 8, 9 and 12 were determined by X-ray single crystal diffraction.Figure optionsDownload as PowerPoint slide