Cyclopropanation of tin-substituted acetals with olefinic alcohols via in situ transacetalization
作者:Masanobu Sugawara、Jun-ichi Yoshida
DOI:10.1016/s0040-4039(99)00035-0
日期:1999.2
Reactions of a tin-substituted acetal with olefinic alcohols in the presence of an acid resulted in facile transacetalization followed by intramolecular cyclopropanation to give the cyclized products in high yields and stereoselectivity.
Hydroalkylation of Alkynyl Ethers via a Gold(I)-Catalyzed 1,5-Hydride Shift/Cyclization Sequence
作者:Igor Dias Jurberg、Yann Odabachian、Fabien Gagosz
DOI:10.1021/ja9100134
日期:2010.3.17
A series of alkynyl ethers react with an electrophilic gold(I) catalyst to produce a range of structurally complex spiro or fused dihydrofurans and dihydropyrans via a 1,5-hydride shift/cyclization sequence. This hydroalkylation process, which is performed under practical experimental conditions, can be applied to terminal as well as ester-substituted alkynes. It allows the efficient conversion of
一系列炔基醚与亲电子金 (I) 催化剂反应,通过 1,5-氢化物转移/环化序列产生一系列结构复杂的螺或稠合二氢呋喃和二氢吡喃。这种在实际实验条件下进行的加氢烷基化过程可应用于末端和酯取代的炔烃。它允许通过将乙烯基金物质亲核加成到氧鎓中间体上,将二级或三级 sp(3) CH 键有效转化为新的 CC 键。形成新的五元或六元环的环异构化过程的立体选择性似乎取决于空间因素和炔烃取代模式。
Metachloropehoxybenzoic acid promoted stereoselective synthesis of 2,5-disubstituted tetrahydrofurans from α or γ-allyl-β-hydroxy esters: A formal synthesis of (±) methyl nonactate
作者:Javed Iqbal、Anu Pandey、Bhanu P.S Chauhan
DOI:10.1016/s0040-4020(01)86451-6
日期:1991.1
A one pot stereoselectivesynthesis of cis or trans 2,5-disubstituted tetrahydrofurans 3–8 can be achieved in high yields via electrophilic cyclisation of the corresponding cis or trans α or γ-allyl-β-hydroxyesters mediated by metachloroperoxybenzoic acid. The tetrahydrofurans 5 or 6 may be converted into (±) methylnonactate by procedures described earlier. The role of methoxycarbonyl group during
treatment of cobalt oxide supported gold nanoparticles (Au/Co3O4) under syngas atmosphere effectively generated a cobalt carbonyl-like active species in the reaction vessel. The preparation of Au/Co3O4 was quite simple and the in situ generated cobalt species could be used as a stable and easy handling alternative for dicobaltoctacarbonyl without bothersome purification prior to use. The reactions, which
在合成气气氛下处理氧化钴负载的金纳米颗粒(Au / Co 3 O 4)可在反应容器中有效生成羰基钴样活性物质。Au / Co 3 O 4的制备非常简单,原位生成的钴物种可以用作八羰基二钴的稳定且易于处理的替代品,而无需在使用前进行麻烦的纯化。该反应对二钴八羰基化合物的纯度敏感,例如环氧化物的烷氧羰基化反应和Pauson-Khand反应,随着Au / Co 3 O 4顺利进行。
2,6-Disubstituted Tetrahydropyrans by Tandem Cross-Metathesis/Iodocyclisation