Radomir N. Saicic

A convenient synthesis of trifluoromethyl aryl sulfides

Abstract Trifluoromethyl aryl sulfides are obtained in moderate/good yields by heating potassium trifluoroacetate and aryl disulfides in sulfolane

A new synthesis of α-tetralones

Abstract α-tetralones 8a-j can be prepared by radical cyclisation, in the presence of stoichiometric amounts of lauroyl peroxide, of xanthates 5a-j obtained by an intermolecular addition of substituted S-phenacyl xanthates 4a-c to various olefins.

Total Synthesis of (−)-atrop-Abyssomicin C†

In 2004, S ssmuth and co-workers reported the isolation of abyssomicin C, a naturally occurring antibiotic of exotic origin and complex structure. The mechanism of antibiotic activity of abyssomicin C against Gram-positive bacteria, including methycillinand vancomycin-resistant Staphylococcus aureus strains, was unprecedented: it inhibits tetrahydrofolate biosynthesis at an early stage. In addition to abyssomicin C, several other congeners have been found in both marine and terrestrial Streptomyces strains (Scheme 1). The combination of strong antibacterial activity

New radical reactions of S-alkoxycarbonyl xanthates. Total synthesis of (±)-cinnamolide and (±)-methylenolactocin

Abstract Irradiation with visible light of S-alkoxycarbonyl xanthates derived from various alcohols gives rise to alkoxycarbonyl radicals with bifurcate reactivity: loss of carbon dioxide leads to deoxygenated derivatives (i.e. alkyl xanthates) whereas intramolecular addition to a suitably located double bond produces lactones; these new reactions were applied to the total synthesis of (±)-cinnamolide and (±)-methylenolactocin.

Radical cyclization reactions. Cyclopropane ring formation by 3-exo-cyclization of 5-phenylthio-3-pentenyl radicals

Abstract Free radical cyclopropane ring closure was accomplished by thermal decomposition of thiohydroxamic esters of 6-phenylthio-4-hexencic acids. When the reaction was performed in the presence of acrylonitrile; an addition/cyclization/elimination process took place and the corresponding cyclopentanecarbonitriles were obtained.

Total synthesis of (±)-cinnamolide and (±)-methylenolactocin–an approach to butenolides using S-alkoxycarbonyl xanthates

The total synthesis of (±)-cinnamolide 9 and (±)-methylenolactocin 15 is accomplished using as the key step a radical cyclisation involving alkoxycarbonyl radicals derived from S-alkoxycarbonyl xanthates.

Free radical annulation of cyclopentane ring

Abstract Homoallyl radical, e.g. 2 , reacts with an electron-deficient olefinic bond 1 with a new CC bond forming and arising of a 5-hexenyl radical 3 which further undergoes to 5-exo-trigonal cyclization with a cyclopentane ring ( 4 ) annulation.

Intermolecular free radical additions to strained cycloalkenes. Cyclopropene and cyclobutene as radical acceptors

Abstract Intermolecular additions of electrophilic radicals to cyclopropene and cyclobutene derivatives afford the addition products in 37–50% yield. The strain relief in the intermediary radical accelerates the addition, as shown by competitive addition experiments.

Alkylation of carbonyl compounds in the TiCl4-promoted reaction of trimethylsilyl enol ethers with ethylene oxide

Abstract Titanium tetrachloride promoted reaction of trimethylsilyl enol ethers with ethylene oxide affords homoaldol type products in moderate/good yields. The reaction is believed to proceed via the titanium enolates.

Free radical phenylthio group transfer to nonactivated δ-carbon atom in the photolysis reactions of alkyl benzenesulfenates

Abstract A free radical phenylthio group transfer from oxygen to the non-activated δ-carbon atom was achieved by irradiation of alkyl benzenesulfenates 1 in the presence of hexabutylditin, and δ-phenylthio alcohols 2 were obtained in 35–91% yields. However, when reactions were performed in the presence of activated olefins an alkylation of δ-carbon occured and phenylthio ethers of type 3 were obtained modest yields.