John Boukouvalas

Diastereoselectivity in the directed aldol condensation of 2-trimethylsiloxyfuran with aldehydes. A stereodivergent route to threo and erythro δ-hydroxy-γ-lactones

Abstract Threo and erythro -δ-hydroxy-α,β-unsaturated γ-lactones are obtained with useful diastereoselection by condensing 2-trimethylsiloxyfuran and aldehydes by varying the reaction reaction conditions. A stereomechanistic rationale is presented together with a practical two-step synthesis of the threo and erythro 5-hydroxy-4-decanolides (L factors).

A New Method for the Synthesis of gem-Dihydroperoxides

The tungstic acid-catalyzed reaction of ketals with hydrogen peroxide provides a convenient and efficient method for preparing gem-dihydroperoxides.

The synthesis of (±)-cavernosine

Abstract The title compound and its epimer were synthesized in three and two steps from dihydro-β-ionone and 2-trimethylsiloxyfuran in 38 and 63% overall yields respectively. Their relative configurations were confirmed by X-ray of an intermediate.

A short route to furanosesquiterpenes using a new siloxyfuran building block. The synthesis of freelingnite and dehydrolasiosperman

Abstract The utility of 2-( tert -butyldimethylsiloxy)-3-methylfuran for the regioselective assembly of furanosesquiterpenes is demonstrated by the syntheses of (±)-freelingnite and dehydrolasiosperman.

A direct synthesis of (±)-eldanolide via the highly regioselective prenylation of 2-trimethylsiloxyfuran

Abstract The reaction of 2-trimethylsiloxyfuran, 3,3-dimethylallyl bromide and silver trifluoroacetate produced (3,3-dimethylallyl)-4-but-2-en-4-olide with high double regiodifferentiation. The latter compound on treatment with lithium dimethylcuprate gave (±)-eldanolide in high yield.

Total synthesis of bromobeckerelide

Abstract The first synthesis of (±)-bromobeckerelide has been accomplished in five steps from 5-methylfurfural by exploiting the regiospecific aldolization of a dialkylboron 2-furanolate.

New chemistry of zwitterionic peroxides arising by photooxygenation of enol ethers

Abstract The rosebengal-sensitized photooxygenation of 2-methoxynorborn-2-ene( 1 )in acetaldehyde gave cis -1-carboxaldehyde-3-carbomethoxycyclopentane (31%) and the cis and trans -Me derivatives of the cis -fuscd exo -1,2,4-trioxanes arising by addition of a molecule of oxygen and acetaldehyde to 1 at C3 and C2 respectively (13%) Similar photooxygenation of 2-(methoxymethylidene)adamantane in the presence of acetaldehyde, propionaldehyde and pivalaldehyde gave adamantanone (31–42%), and the cis and trans tricylo[3.3.1.1 3,7 ]decane-2-spiro-6-[3-alkyl-5-methoxy-1,2,4-trioxanes] in yields of 32–53% Trioxane formation under similar conditions was experienced for 1,1-di-t-butyl-2-methoxyethene and 2-(methylmercaptomethylidene) adamantane. The results are discussed in terms of an intermediate zwitterionic peroxide which can either close directly to a 1,2-dioxetane or, if aldehyde is present, condense across the CO function giving the 1,2,4-trioxane.

A short, stereodivergent synthesis of the racemic erythro and threo diastereomers of 6-acetoxy-5-hexadecanolide, a mosquito oviposition attractant pheromone

Abstract A versatile 3-step synthesis of the title lactones has been accomplished by the stereocontrolled addition of n -decylmetallic reagents to acrolein dimer.

Regioselective aldol condensations of boron and tin furanolates with aldehydes: an improved synthesis of 2-(1′-hydroxyalkyl)butenolides

Boron and tin(II) 2-furanolates generated in situ from 2-(5H)-furanone and α-angelica lactone undergo regioselective aldolization with aldehydes to furnish the corresponding 2-(1′-hydroxyalkyl)butenolides in good yields; a new formal synthesis of (±)-litsenolide C1 and (±)-dihydromahubanolide is described.

The alkylation of silyl enol ethers with SN1-unreactive iodides in the presence of silver trifluoroacetate

Abstract Silyl enol ethers can be effectively alkylated with primary n-alkyl iodides in the presence of silver trifluoro-acetate to give monoalkyl ketones.