This article reports the synthesis of novel 2',3',4'-trimethyl branched carbocyclic nucleosides. The introduction Of a methyl group in the 2' and 3'-position was accomplished by sequential Horner Wadsworth-Emmons reaction and isopropenyl magnesiumbromide addition, respectively. The construction of the 4'-quaternary carbon needed was carried out using a [3,3]-sigmatropic rearrangement. Bis-vinyls were successfully cyclized using a Grubbs catalyst II. The natural bases (adenine, cytosine) were efficiently coupled with the use of a Pd(0) catalyst.
Using Nazarov Electrocyclization to Stage Chemoselective [1,2]-Migrations: Stereoselective Synthesis of Functionalized Cyclopentenones
作者:David Lebœuf、Jie Huang、Vincent Gandon、Alison J. Frontier
DOI:10.1002/anie.201104870
日期:2011.11.11
Highly functionalizedcyclopentenones have been prepared stereospecifically through a chemoselective copper(II)‐mediated Nazarov/Wagner–Meerwein rearrangement sequence. After the initial 4π electrocyclization, this reaction involves two sequential [1,2]‐migrations depending upon both migratory ability and steric bulk of the substituents at C1 and C5 (see scheme). The proposed mechanism of the reaction
Synthesis and Anti-HCMV Activity of Novel 2',3',4'-Trimethyl Branched Carbocyclic Nucleosides
作者:Aihong Kim、Joon Hee Hong
DOI:10.1081/ncn-200046786
日期:2005.1.1
This article reports the synthesis of novel 2',3',4'-trimethyl branched carbocyclic nucleosides. The introduction Of a methyl group in the 2' and 3'-position was accomplished by sequential Horner Wadsworth-Emmons reaction and isopropenyl magnesiumbromide addition, respectively. The construction of the 4'-quaternary carbon needed was carried out using a [3,3]-sigmatropic rearrangement. Bis-vinyls were successfully cyclized using a Grubbs catalyst II. The natural bases (adenine, cytosine) were efficiently coupled with the use of a Pd(0) catalyst.