Application of the diastereoselective photodeconjugation of α,β-unsaturated esters to the synthesis of gymnastatin H
نویسندگان
چکیده
The asymmetric synthesis of gymnastatin H has been achieved by using the photoisomerisation of a conjugated ester to its β,γ-unsaturated isomer through the protonation of a in situ generated dienol as key step. Thanks to diacetone D-glucose used as a chiral alkoxy group, the protonation occurred well onto one of the two diastereotopic faces with very high yields and selectivities. Moreover, by this way the configuration of the C-6 centre of the target molecule was controlled.
منابع مشابه
Phosphine-catalyzed highly diastereoselective [3+2] cyclization of isatin derived electron-deficient alkenes with α-allenic esters.
A novel phosphine-catalyzed highly diastereoselective [3+2] cycloaddition of isatin derived α,β-unsaturated ketones with α-allenic ester has been developed.
متن کاملMicrowave assisted Pd(OAc)2-catalyzed chemoselective reduction of aryl α,β-unsaturated esters with triethylsilane
< p>In this communication, we have reported that the Pd(OAc)2–Et3SiH-DMF system promotes the microwave-assisted chemoselective reduction of aryl α,β-unsaturated esters in good yields. The protocol affords a convenient reduction of aryl-conjugated double bonds even in presence of other functional groups like esters, phenols, and ethers.
متن کاملDiastereoselective Synthesis of Stable Phosphorus Yields by a Three-Component Reaction between Ph3P and Acetylenic Esters in the Presence of Hydrazine Derivatives
In this work, stable crystalline phosphorus yields are obtained in good yields from the 1:1:1 addition reactions between hydrazine derivatives and dialkyl acetylenedicarboxylates in the presence of triphenylphosphine at room temperature in dichloromethane. This synthetic method has merits of high yields, mild reaction conditions, and simple experimental and work-up conditions. The obtained yiel...
متن کاملPolyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3): An efficient catalyst for the synthesis of chromenylphenylpropanones
An efficient synthesis of chromenylphenylpropanone derivatives as warfarine-like analogues was developed by the Michael addition of 4-hydroxycoumarin to α,β-unsaturated compounds in the presence of polyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3) as a new polymeric Lewis acid catalyst in chloroform at reflux conditions without formation of 2,4-...
متن کاملPolyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3): An efficient catalyst for the synthesis of chromenylphenylpropanones
An efficient synthesis of chromenylphenylpropanone derivatives as warfarine-like analogues was developed by the Michael addition of 4-hydroxycoumarin to α,β-unsaturated compounds in the presence of polyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3) as a new polymeric Lewis acid catalyst in chloroform at reflux conditions without formation of 2,4-...
متن کامل