A [3 + 2] Dipolar Cycloaddition Route to 3-Hydroxy-3-alkyl Oxindoles: An Approach to Pyrrolidinoindoline Alkaloids
摘要:
A [3 + 2] cycloaddition approach to the 3-hydroxy-3-alkyl oxindole scaffold is described. Isoxazolines obtained by cycloaddition of nitrile oxide 3 with 3-methylene oxindoles were elaborated to 3-hydroxy-3-cyanomethyl oxindoles employing a one-pot protocol en route to the pyrrolidinoindoline moiety which is found in many natural products. The total syntheses of alkaloids (+/-)-alline and (+/-)-CPC-1 were achieved using this methodology.
Domino Rh-catalyzed hydroformylation–double cyclization of o-amino cinnamyl derivatives: applications to the formal total syntheses of physostigmine and physovenine
A parallel, versatile and efficient route to synthesis of pyrrolidinoindoline and tetrahydrofuranoindoline alkaloids from cinnamyl derivatives has been developed, featuring a domino Rh-catalyzed hydroformylationâdouble cyclization sequence. This method can be applied to the syntheses of anti-Alzheimer drugs such as physostigmine and physovenine.
First asymmetric decarboxylative cyanomethylation of isatins is reported herewith using bifunctional thiourea derived from L-proline in good yields and enantioselectivities. This strategy enables the construction of various 3-cyanomethylene substituted 3-hydroxyoxindoles in enantioselective manner. Enantioselective synthesis of CPC-1 alkaloid has been accomplished in fewer steps.
The first syntheticallyuseful interrupted Witkop oxidation has been disclosed through a radical triggered oxidative peroxycyclization of tryptamine derivatives, using a TBAI/TBHP catalytic system. This differs from known tryptophan oxidations, which typically cleave the 2,3-double bond. Upon one-pot reduction, this system renders an easy access to structurally distinct peroxypyrroloindoles, which
Copper-catalyzed aerobic oxidative radical alkoxycyclization of tryptamines to access 3-alkoxypyrroloindolines
作者:Wei Wang、Jun-Rong Song、Zhi-Yao Li、Ting Zhong、Qin Chi、Hai Ren、Wei-Dong Pan
DOI:10.1039/d1ra02679h
日期:——
An oxazoline/copper-catalyzed cascade carboamination alkoxylation of substituted tryptamine under mild eco-friendly O2 oxidation conditions was reported.