Copper-catalyzed allylations of zirconocene intermediates generated from o-alkenyl or o-alkynylbenzyl ether derivatives and zirconocene-butene complex.
o-Alkenyl or alkynyl benzylzirconocene intermediate, which was readily generated by the reaction of 2-alkoxymethylstyrene or 2-alkoxymethyl-1-(trimethylsilylethynyl)-benzene derivative with zirconocene-butene complex (Negishi reagent, "Cp2Zr"), reacted with allyl or propargyl halides in the presence of a catalytic amount of CuCl to give allylation or allenylation products. Conversion to Dane's diene, which is a key intermediate for estrone synthesis, was efficiently carried out by enyne olefin metathesis of the allylation products.
Ikeuchi
Yutaka
Y
Sankyo Co., Ltd., 1-12-1, Shinomiya, Hiratsuka-shi, Kanagawa 254-8560, Japan.
Taguchi
Takeo
T
Hanzawa
Yuji
Y