201274-51-3Relevant academic research and scientific papers
Fusicoccin ring system by [4 + 4] cycloaddition. 2. A model study
Sieburth, Scott McN.,McGee Jr., Kevin F.,Al-Tel, Taleb H.
, p. 4007 - 4010 (1999)
A synthetic approach to fusicoccin A utilizing intramolecular photocycloaddition of tethered 2-pyridones has been completed. This study has led to the first solvent-dependent 2-pyridone photocycloaddition yielding either cis or trans products. Epoxidation of the cis photoproduct is selective for the disubstituted alkene, stabilizes the product, and is properly located for installation of the trans-1,2-diol. Activation of the secondary amide by reaction with an isocyanate led to the reduction of the neopentyl amide carbonyl to a methyl group.
Fusicoccin synthesis by intramolecular [4+4] photocycloaddition of 2-pyridones: Stereocontrol of the cycloaddition and elaboration of the pentacyclic product
McGee Jr.,Al-Tel,Sieburth
, p. 1185 - 1196 (2007/10/03)
Intramolecular photocycloaddition of a three-carbon tethered pyrindinone-pyridone system yields the 5-8-5 ring system of the fusicoccin/ophiobolin/ceroplastol families. The stereoselectivity of the cycloaddition was found to be dependent on nitrogen substitution; N-methylation led to exclusively trans products while an absence of nitrogen substitution resulted in solvent-dependent stereoselectivity. Solvent and concentration effects for this cycloaddition were consistent with a hydrogen-bonded dimer that enforces a pro-cis conformation in nonpolar solvents and at higher concentrations. The cis-isomer, a fusicoccin synthesis intermediate, underwent a Cope rearrangement at ambient temperature but could be trapped efficiently as the mono epoxide, yielding a product with six new stereogenic centers. A four-step transformation of an amide carbonyl to a methyl group was achieved using a carbamoyl group to activate the amide for cleavage.
