将在其系链中掺入一个双键的全甲基环戊二烯基系链氯化钛(IV)的溶液在玻璃容器中暴露于阳光下,这触发了它们的光解反应,提供了产物的混合物。尽管从1 H NMR光谱可以明显看出几种不同产物的形成,但在粗反应混合物中只能鉴定出一种产物。该产物是二环戊二烯[C 10 Me 10 ],其是由通常光解离的C 5 Me 5自由基的重组产生的。在含钛产品中,有三种配合物(3a,3b和4a可以通过分步结晶分离得到,并对这些配合物进行表征。的机构3a中形成包括一个η的光解5 -C 5我5从父络合物配体,从另一种反应物分子被氯抽象补充。配合物3b和4a通过系链重排而形成,该过程首先是断开系链Ti-C键,然后旋转系链,随后使其重新连接通过其可用的自由基末端。
Regioselective Homo- and Codimerization of 1-Alkynes Leading to 2,4-Disubstituted 1-Buten-3-ynes by Catalysis of a (η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>TiCl<sub>2</sub>/RMgX System
作者:Munetaka Akita、Hajime Yasuda、Akira Nakamura
DOI:10.1246/bcsj.57.480
日期:1984.2
A series of 1-alkynes (RC≡CH where R=Et, n-Pr, n-Bu, n-C6H13, cyclohexyl, Ph, Me3Si, Me3SiCH2, and Me3SiOCH2) was found to dimerize regioselectively (>99%) to 2,4-disubstituted 1-buten-3-ynes in 92–99% yields by catalysis of (η5-C5Me5)2TiCl2/i-PrMgBr at 30 °C in 1–3 h. The catalyst system is also effective for the regioselective codimerization of various 1-alkynes with 1-ethynylcyclohexene or ethynylbenzene.
The singly tucked-in permethyltitanocene 1 reacts with an excess of internalalkynes to give the 1:1 adducts 3a−c,f−i, arising from insertion of the alkyne triple bond into the titanium−methylene bond. Only the simplest species, 2-butyne, inserted two molecules to give the known compound 2; however, at a 1:1 stoichiometric ratio the 1:1 adduct 3j was also smoothly formed. 1,4-Disubstituted conjugated
Skeletal change in the PNP pincer ligand leads to a highly regioselective alkyne dimerization catalyst
作者:Wei Weng、Chengyun Guo、Remle Çelenligil-Çetin、Bruce M. Foxman、Oleg V. Ozerov
DOI:10.1039/b511148j
日期:——
A Rh complex of a bulky diarylamino-based PNP pincer ligand is a robust catalyst for the dimerization of terminal alkynes and highly selective for the trans-enyne product.
Unprecedented isolation of alk-1-en-3-yn-1-yl intermediates in the catalytic oligomerisation of alk-1-ynes by cationic Lewis base-free zirconocene complexes
作者:Andrew D. Horton
DOI:10.1039/c39920000185
日期:——
[Zr(C5Me5)2Me(4-C6H4F)4}]1 catalyses the rapid regioselective oligomerisation of RCCH to 2,4-disubstituted-but-1-en-3-ynes (R = But, Prn, Me, Ph, 4-C6H4Me) and 1,4,6-trisubstituted-hexa-1,3-dien-5-ynes (R = Prn, Me); isolation of the unprecedented crystalline complexes, [Zr(C5Me6)2CHC(R)CCR}]+(R = But2a, Prn2b) and [Zr(C5Me5)2C(SiMe3)CHCHC(SiMe3)CCSiMe3}]+3f, provides firm evidence for the catalytic
[Zr(C 5 Me 5)2 Me (4-C 6 H 4 F)4 }] 1催化RC CH快速区域选择性低聚为2,4-二取代-丁-1-烯-3-炔(R = Bu t,Pr n,Me,Ph,4-C 6 H 4 Me)和1,4,6-三取代-六-1,3-dien-5-ynes(R = Pr n,Me);分离出前所未有的晶体配合物[Zr(C 5 Me 6)2 CH C(R)C CR}] +(R = Bu t 2a,Pr n 2b)和[Zr(C 5 Me 5)2 C(SiMe 3)CHCH C(SiMe 3)C CSiMe 3 }] + 3f提供了催化循环的确凿证据。
Selimov, F. A.; Rutman, O. G.; Dzhemilev, U. M., Journal of Organic Chemistry USSR (English Translation), 1983, vol. 19, p. 1621 - 1624