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。
A One-Step Synthesis of Alkyl 2-Oxo-3-alkenoates from Alkenyl Grignard Reagents and Dialkyl Oxalates
作者:M. Rambaud、M. Bakasse、G. Duguay、J. Villieras
DOI:10.1055/s-1988-27642
日期:——
The reaction of alkenyl Grignard reagents with dialkyl oxalates at 80°C in an ether/tetrahydrofuran mixture (1:1) leads to the formation of the corresponding alkyl 2-oxo-3-alkenoates in high yields. Thus a mild and convenient one-step synthesis of 3-isopropenyl-substituted 2-oxoesters is described.
A bioinspired radical oxidative α-oxyamination of pyruvate with an oxoammonium salt through multiple-site concerted proton–electron transfer process has been developed, which was facilitated by anchoring the mercapoto chains as a “hopping” site at the γ-position of α-keto esters.
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
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。