Sequentially rhodium-catalyzed enantioselective cycloisomerization–hydrogenation syntheses of alkylidene butyrolactone β-hydroxyethanes and alkylidene tetrahydrofuran β-aminoethanes
作者:Nadine Muschelknautz、Frank Rominger、Thomas J. J. Müller
DOI:10.1007/s10593-018-2267-1
日期:2018.3
and ether-tethered alkyne allyl alcohols is an excellent entry to subsequent Rh-catalyzed one-pot hydrogenations in the sense of sequentially Rh-catalyzed processes to chiral alkylidene butyrolactone β-hydroxyethanes and alkylidene tetrahydrofuran β-aminoethanes, respectively, with excellent levels of enantioselectivity.
A Highly Reusable Rhodium Catalyst-Organic Framework for the Intramolecular Cycloisomerization of 1,6-Enynes
作者:Elizabeth G. Corkum、Michael J. Hass、Andrew D. Sullivan、Steven H. Bergens
DOI:10.1021/ol201333s
日期:2011.7.1
The intramolecular cycloisomerization of 1,6-enynes in 95-99% ee is reported using an immobilized Rh catalyst-organic framework synthesized from alternating ring-opening metathesis polymerization (altROMP) assembly. The framework was reused up to seven times, and it was used in high turnover number (TON) batch reactions. The catalyst provided the highest TONs to date (up to 890) for the cycloisomerizations, with catalyst loadings ranging from 0.2 to 0.06 mol %.
Highly Enantioselective Syntheses of Functionalized α-Methylene-γ-butyrolactones via Rh(I)-catalyzed Intramolecular Alder Ene Reaction: Application to Formal Synthesis of (+)-Pilocarpine
作者:Aiwen Lei、Minsheng He、Xumu Zhang
DOI:10.1021/ja020052j
日期:2002.7.1
Rh(I)-catalyzed intramolecular Alderenereaction has been developed. The desired products, 3-vinyl, vinyl acetate, and vinyl ether-substitued α-methylene-γ-butyrolactones were formed in high yields. Aldehydes were produced with the formation of γ-lactones when alcohols were substituted at allylic position in the substrates. All reactions with listed substrates proceeded in over 99% ee. A formal synthesis of (+)-pilocarpine
已开发出高度对映选择性的 Rh(I) 催化的分子内阿尔德烯反应。以高产率形成了所需的产物 3-乙烯基、乙酸乙烯酯和乙烯基醚取代的 α-亚甲基-γ-丁内酯。当醇在底物的烯丙基位置被取代时,随着γ-内酯的形成而产生醛。与所列底物的所有反应均以超过 99% 的 ee 进行。(+)-毛果芸香碱的正式合成是证明该方法的合成效用的极好例子。