Pyridine Core Activation <i>via</i> 1,5-Electrocyclization of Vinyl Pyridinium Ylides Generated from Bromo Isomerized Morita−Baylis−Hillman Adduct of Isatin and Pyridine: Synthesis of 3-Spirodihydroindolizine Oxindoles
5-electrocyclization of vinyl pyridiniumylides generated from bromo isomerized Morita−Baylis−Hillman adducts of isatin and pyridine under basic conditions. The method has been successfully applied for an efficient synthesis of a number of 3-spirodihydroindolizine-2-oxindoles, which have been found as core structure of secoyohimbane and heteroyohimbane alkaloid natural products.
Stereoselective Synthesis of Geometrically Strained, Oxindole-Appended Vinyl Cyclopropanes and Highly Substituted Cyclopentenes via Sulfur Ylide Cyclopropanation and Vinyl Cyclopropane Rearrangement
An efficient diastereoselective synthesis of oxindole-appended vinyl cyclopropanes from bromo isomerised Morita-Baylis-Hillman adducts of isatin with activated alkylidene and isatilidines via sulfur ylide cyclopropanation reaction have been achieved. The synthesised vinyl cyclopropanes have undergone vinyl cyclopropane rearrangement and [3+2] cycloaddition with an allene to afford dispiro bisoxindole
A Short and Efficient Synthesis
of 3-Spiro-α-methylene-γ-butyrolactone Oxindolones
from Isomerised Bromo Derivatives of Morita-Baylis-Hillman Adducts
作者:Ponnusamy Shanmugam、Baby Viswambharan
DOI:10.1055/s-0028-1083549
日期:——
A short and efficientsynthesis of α-methylene-γ-butyrolactone-3-spirooxindolones by the reaction of isomerised bromo derivatives of Morita-Baylis-Hillmanadducts of isatin and formaldehyde followed by acid-catalysed lactonisation has been achieved. The oxindolidino allyl bromide has been used for the first time for the allylation of aldehydes to afford a 2-oxindolidino homoallylic alcohol which on
chemistry phosphorus and sulfur ylides have been exploited for a facile, short and efficient synthesis of 3-spirocyclopentene- and 3-spiropyrazole-2-oxindoles from E- and Z-isomers of bromo derivatives of Morita-Baylis-Hillman adducts of isatin with Ph(3)P/activated alkene/K(2)CO(3) and Me(2)S/DEAD/K(2)CO(3), respectively, via [3 + 2]-annulation strategy.
磷和硫的化学信息已被用于由Isita的Morita-Baylis-Hillman加成物的溴衍生物的E-和Z-异构体轻松快速,短而有效地合成3-spirocyclopentene-和3-spiropyrazole-2-oxindoles Ph(3)P /活化的烯烃/ K(2)CO(3)和Me(2)S / DEAD / K(2)CO(3),分别通过[3 + 2]-环化策略。