A new ring for your indole: An unprecedented copper‐catalyzed enantioselectiveFriedel–Craftsalkylation/N‐hemiacetalization cascade reaction with indoles and β,γ‐unsaturated α‐ketoesters is reported. This mild strategy provides new access to various synthetically and biologically important 2,3‐dihydro‐1H‐pyrrolo[1,2‐a]indoles in a highlyenantioselective manner.
吲哚的新环:据报道,铜与吲哚和β,γ-不饱和α-酮酸酯发生了前所未有的铜催化对映选择性Friedel-Crafts烷基化/ N-半缩醛化级联反应。这种温和的策略以高度对映选择性的方式为各种合成和生物学上重要的2,3-二氢-1 H-吡咯并[1,2- a ]吲哚提供了新途径。
Zinc(II)-Catalyzed Asymmetric Diels–Alder Reaction of (<i>E</i>)-1-Phenyl Dienes with β,γ-Unsaturated α-Ketoesters
diastereo-, and enantioselective Diels–Alderreaction of β,γ-unsaturated α-ketoesters with (E)-1-phenyl dienes has been accomplished by using a stable and easily available chiral N,N′-dioxide/zinc(II) complex as catalyst. Only one isomer of the corresponding cyclohexenes with three chiral centers was obtained in good to excellent yields with excellent ee values under mild reaction conditions. The configurations
direct Friedel–Craftsreaction of chromene hemiacetals with indoles, furans and sterically hindered anilines has been accomplished with high selectivity and excellent yields in the presence of a catalytic amount of hafnium triflate [Hf(OTf)4, 0.1 mol%, 0–40 °C]. The mild conditions tolerate various sensitive functional and protecting groups, and the products were confirmed unambiguously from their spectra
Catalytic Generation of Donor-Acceptor Cyclopropanes under <i>N</i>
-Heterocyclic Carbene Activation and their Stereoselective Reaction with Alkylideneoxindoles
作者:Liher Prieto、Eduardo Sánchez-Díez、Uxue Uria、Efraím Reyes、Luisa Carrillo、Jose L. Vicario
DOI:10.1002/adsc.201700198
日期:2017.5.17
Formylcyclopropanes undergo activation in the presence of an N‐heterocyclic carbene catalyst generating a donor‐acceptorcyclopropane intermediate with the ability to undergo ring‐opening followed by formal [4+2] cycloaddition with alkylideneoxindoles. This enables the direct enantio‐ and diastereoselective synthesis of tetrahydropyrano[2,3‐b]indoles through the use of a chiral NHC catalyst.
甲酰基环丙烷在N杂环卡宾催化剂的存在下发生活化,生成供体-受体环丙烷中间体,该中间体具有开环能力,然后与亚烷基亚氧吲哚进行正式的[4 + 2]环加成反应。这样可以通过使用手性NHC催化剂直接对映和非对映选择性合成四氢吡喃并[2,3- b ]吲哚。
Enantioselective phospha-Michael addition of diarylphosphines to β,γ-unsaturated α-ketoesters and amides
作者:Renta Jonathan Chew、Kai Yuan Teo、Yinhua Huang、Bin-Bin Li、Yongxin Li、Sumod A. Pullarkat、Pak-Hing Leung
DOI:10.1039/c4cc01610f
日期:——
A chiral palladacycle catalyzed hydrophosphination of β,γ-unsaturated α-ketoesters and amides has been developed; with up to 99% yield and 90% ee.