Palladium-catalysed annulation of β-chloro-α,β-unsaturated esters with internal alkynes leading to 2H-pyran-2-ones
作者:Ruimao Hua、Masato Tanaka
DOI:10.1039/b007620l
日期:——
Heteroannulation
of β-chloro-α,β-unsaturated esters with internal alkynes proceeded in the presence of triethylamine
and palladium complexes, bis(triphenylphosphine)palladium species in particular, to afford to 2H-pyran-2-ones.
Treatment of methyl (Z)-3-chloro-2-heptenoate with Pd(PPh3)4 generates [(Z)-1-butyl-2-methoxycarbonylethenyl]chlorobis(triphenylphosphine)palladium ia oxidative addition, which gives the corresponding 2H-pyran-2-one upon addition
of 4-octyne. Terminal alkynes also reacted with β-chloro-α,β-unsaturated esters, but the major products were
β-alkynylated α,β-unsaturated
esters.
在三乙胺和钯络合物(特别是双(三苯基膦)钯物种)的存在下,β-氯-α,β-不饱和酯与内炔进行杂环化反应,生成2H-吡喃-2-酮。用Pd(PPh3)4处理甲基(Z)-3-氯-2-庚烯酸酯,通过氧化加成生成[(Z)-1-丁基-2-甲氧羰基乙烯基]氯双(三苯基膦)钯,在加入4-辛炔后得到相应的2H-吡喃-2-酮。末端炔烃也能与β-氯-α,β-不饱和酯反应,但主要产物是β-炔基化的α,β-不饱和酯。