Synthesis of a novel alpha-diimine palladium(II) complex bearing an eta(3)-allyl gamma-lactone ligand, a key intermediate in alkyne cyclocarbonylation processes

摘要

Reactivity of [Pd(CH3)(CO)(Pr(i)DAB)(+)[B{3,5-(CF3)(2)C6H3}(4)](-) (1), where Pr(i)DAB = 1,4-diisopropyl-1,4diaza-1,3-butadiene, toward alkynes and carbon monoxide was investigated. While the reaction of 1 with phenylacetylene produced stereoregular homopolymer, a stoichiometric insertion of 1-phenyl-1-propyne and 2-butyne into the Pd-acyl bond yielded the palladacycles 2 and 3; subsequent reaction with CO resulted in the formation of novel complexes 4 and 5, which represent the first experimental evidence of a key intermediate in alkyne cyclocarbonylation processes. [References: 41]