Chemoselective functionalization of zirconacyclopentenes
作者:Koichiro Aoyagi、Kayoko Kasai、Denis Y. Kondakov、Ryuichiro Hara、Noriyuki Suzuki、Tamotsu Takahashi
DOI:10.1016/0020-1693(94)09884-0
日期:1994.6
produced as by-products. Reactions of zirconacyclopentenes with an excess of MeOH and iodine in this order gave only alkenyl iodides with excellent selectivities. The formation of diiodides was not detected. This monohalogenation procedure using an excess of MeOH/I 2 was not substituent dependent in the system used here. Treatment of alkylsubstituted zirconacyclopentenes with CBr 4 or CCl 3 Br yielded only
tetrahydroisoquinoline derivatives in good to high yields. This procedure was also used for the selective preparation of benzene derivativesfrom three different alkynes. The use of trimethylsilyl-substituted alkyne as the first, second or third alkyne afforded desilylated benzene derivatives. The reaction of zirconacyclopentadienes with allenes gave benzene derivatives as a mixture of two isomers.
further treatment of the reaction mixture with PhI in the presence of a catalytic amount of Pd(PPh3)4 gave 1,3,4-triphenyl-1-silyl-1,3-butadiene compound 16. Zirconacyclopentadienes with an alkynylsilyl group at the α-position afforded zirconacyclohexadiene derivatives 19 in 82−98% yields. Wh...
Dibutyl zirconocene-mediated trans-selective cyclization of methoxyallyl-ene followed by the reaction with electrophiles is a convenient method for the synthesis of functionalized cyclopentane derivatives. Ring-closing metathesis of the obtained cyclopentane derivative yielded a common building block for the synthesis of sesquiterpene analogues with unnatural trans-[3.4.0]bicyclo-nonane skeleton.
Copper-mediated reaction of oxazirconacyclopentenes with dichlorophenylphosphine: a new pathway for the formation of 1,2-oxaphosphole derivatives
作者:Yiqing Zhou、Sheng Wang、Chao Chen、Chanjuan Xi
DOI:10.1039/c5ra13818c
日期:——
CuCl-mediated reaction of oxazirconacyclopentenes with dichlorophenylphosphine afforded dihydrooxaphospholes in high yields, in which the reaction was performed conveniently in one-pot from an alkyne, carbonyl compound and dichlorophosphine.