A novel tetramer copper(I) complex containing diallylphosphine ligands: Synthesis, characterization and catalytic application in A3-coupling (Aldehyde-Amine-Alkyne) reactions

Article abstract of DOI:10.1016/j.ica.2017.07.038

A novel tetrameric copper(I) complex containing tert-butyldiallylphosphine ligands, [CuCl{^tBu-P(CH₂CH = CH₂)₂}]₄ (2), has been synthesized and characterized by structural and spectroscopic methods. X-ray diffraction analysis showed that 2 has a cubane-like solid structure of formula [CuCl{κ¹(P)-^tBu-P(CH₂CH = CH₂)₂}]₄. In solution, a dynamic behavior generated by the cubane ? chair isomerization was detected by variable temperature NMR analysis. DFT calculations have been performed to explain the observed dynamic equilibrium in solution. The use of copper(I) complex 2 as catalyst for the synthesis of propargylamines via A³-coupling reactions has been tested. Complex 2 is capable of promoting A³-coupling reactions of both aromatic and aliphatic aldehydes with cyclic secondary amines and phenylacetylene. The reaction proceeds under mild condition and absence of solvent.