An Expeditious Route to<i>trans</i>-Configured Tetrahydrothiophenes Enabled by Fe(OTf)<sub>3</sub>-Catalyzed [3+2] Cycloaddition of Donor-Acceptor Cyclopropanes with Thionoesters
A synthetic route to trans‐configured tetrahydrothiophenes (THTs) through Fe(OTf)3‐promoted [3+2] cycloaddition of donor–acceptor cyclopropanes with thionoesters was developed. The cycloaddition proceeded in high yield with high diastereoselectivity, affording transient α‐alkoxy THTs. Not only aromatic and aliphatic thionoesters, but also thionolactone were applicable to the present iron catalysis
A highly enantioselective isocyanide-based multicomponent reaction catalyzed by a chiral N,N′-dioxide/MgII complex was reported. A wide range of substrates were tolerated in this reaction, including alkyl- and aryl-substituted isocyanides with alkylidene malonates and various phenols, affording the corresponding phenoxyimidate products in good to excellent yields (up to 94% yield) with good to excellent
报道了一种由手性N , N ' -二氧化物 / Mg II 配合物催化的高对映选择性异氰化物基多组分反应。在该反应中可以耐受多种底物,包括烷基和芳基取代的异氰化物与亚烷基丙二酸酯和各种酚,以良好至极好的产率(高达 94% 的产率)提供相应的苯氧基亚胺酸酯产物,具有良好至极好的对映选择性(高达到 95.5: 4.5 er)。提出了催化循环和过渡态来合理化反应过程和对映控制。
Indium(III)-Catalyzed Knoevenagel Condensation of Aldehydes and Activated Methylenes Using Acetic Anhydride as a Promoter
amount of InCl3 and aceticanhydride remarkably promotes the Knoevenagel condensation of a variety of aldehydes and activated methylene compounds. This catalytic system accommodates aromatic aldehydes containing a variety of electron-donating and -withdrawing groups, heteroaromatic aldehydes, conjugate aldehydes, and aliphatic aldehydes. Central to successfully driving the condensation series is the formation
Asymmetric Michael Addition of Ketones to Alkylidene Malonates and Allylidene Malonates via Enamine–Metal Lewis Acid Bifunctional Catalysis
作者:Lu Liu、Ryan Sarkisian、Zhenghu Xu、Hong Wang
DOI:10.1021/jo301070s
日期:2012.9.7
Novel enamine–metal Lewis acid bifunctional catalysts were successfully applied to the asymmetric Michaeladdition of ketones to alkylidenemalonates, offering excellent stereoselectivity (up to >99% ee and >99:1 dr). The asymmetric Michaeladdition of ketones to allylidene malonates was also achieved.
Silver Hexafluoroantimonate-Catalyzed Three-Component [2+2+1] Cycloadditions of Allenoates, Dual Activated Olefins, and Isocyanides
作者:Jian Li、Yuejin Liu、Chunju Li、Xueshun Jia
DOI:10.1002/adsc.201000795
日期:2011.4.18
The intermolecular [2+2+1] multicomponent cycloadditions from readily available allenoates, dual activated olefins and isocyanides catalyzed by silver hexafluoroantimonate were studied. This protocol allowed the syntheses of highly functionalized five‐membered carbocycles with exclusive regioselectivity and stereoselectivity in an efficient and atom‐economical manner.