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Reductive cyclization of sulfur-containing substrates 1 and 5 with samarium diiodide afforded the corresponding thiochroman derivatives with excellent diastereoselectivities. Cyclization of 1 is facilitated by geminal dimethyl substitution, which accelerates the reductive coupling and prevents samarium diiodide induced dehalogenation. Bromo-substituted dihydrothiochroman derivative 8 was further functionalized in subsequent reactions. Analogously, bromo-substituted hexahydroquinoline derivative 10 was diastereo­selectively prepared in satisfying yield.

ZnCl 2 (5 mol%) is an efficient catalyst for the thiolysis of 1,2-epoxides by thiophenol in water at pH 4.0. A variety of β-hydroxy phenylsulfides were obtained in short reaction times and excellent yields. Starting from cyclohexene oxide (1), two one-pot multi-step procedures in sole water (thiolysis/oxidation with H 2 O 2 ) have been realized, for the chemoselective synthesis of the corresponding β-hydroxysulfoxides 19 or for the related β-hydroxysulfone 20.

A simple and efficient synthesis of N-nitroethylenediamine derivatives was carried out by reaction of 1-nitroimidazolidin-2-one with various nitrogen-, oxygen-, and sulfur-containing nucleophiles. The reactivity of primary and secondary amines, amino alcohols, hydrazines, amino acids, alcohols, and thiophenol was tested.

The treatment of alkynylselenonium salts and thiophenol derivatives with a catalytic amount of triethylamine afforded β-arylthiovinylselenonium salts in good yields. The reactions of the vinylselenonium salts with nucleophiles produced (Z)-β-arylthio-α-functionalized ethenes in high yields. In addition, the vinylselenonium salts bearing a hydroxy group, 2d-f, 2h, underwent intramolecular cyclization upon treatment with sodium hydride to produce medium-membered heterocyclic compounds containing S and O atoms.

Reaction of p-toluenesulfinyl amines with thiophenol in the presence of catalytic amount of ZnCl 2 provides the corresponding desulfinylated amines in high yield.

Cyclic and open-chain benzylic ethers undergo cleavage by thiophenol on the surface of silica gel impregnated with indium(III) chloride under microwave irradiation to produce the corresponding di- and monothioethers.

(A) The reaction of O-alkyl isoureas with carboxylic acids affords the corresponding esters. 2 Even though ester can be conveniently prepared by a one-pot reaction from carboxylic acid, alcohol and carbodiimide. The method via O-alkyl isourea provides an inversion of the alkyl configuration in case of a chiral one. 3 S-alkyl thioate can be obtained from thioic S-acid. 4 (B) The reaction of polymer-supported O-methyl, O-benzyl, and O-allyl isoureas with carboxylic acids provides the corresponding alkyl esters in high yields and purity. The reaction can be finished in 3 to 5 minutes with microwave heating, without compromising yield, purity, or chemoselectivity. 5 (C) Phosphate esters could be obtained via the reaction of O-alkyl isoureas with phosphoric acid. 6 (D) O-alkyl isoureas can be efficiently converted into alkyl bromides and iodides by treatment with one mol equivalent of trifluoromethanesulphonic acid in the presence of an excess of tetrabutylammonium bromide or iodide. The conversion can be performed either with the pure isolated O-alkyl isourea or with (E) Linclau and co-workers reported that primary and secondary alcohols were converted into the corresponding alkyl halide via the corresponding O-alkyl isoureas. High yields could be obtained in the case of chlorides and bromides. This method tolerates a range of functional groups and does not rely on the use of phosphines. 8 (F) Linclau also reported that N-(β-hydroxy)amides could be cyclized with diisopropylcarbodiimide (DIC) to give the corresponding 2-oxazolines in high yields. The reaction requires only very mild Lewis acid catalysis [5mol% Cu(OTf) 2 ] and can be accomplished with conventional heating or under microwave irradiation. 9 (G) The reaction of O-alkyl isoureas with N-acylsulfonamide gave the N-alkylated products. The reaction can be carried out with polymer-bound sulfonamide.10 (H) Phenol ether and thiophenolether can be prepared via the reaction of O-alkyl isoureas with phenol and thiophenol, respectively. 11,12 (I) O-alkyl isoureas were reported as allyl reagents in C-C bond formation reactions in the presence of a palladium catalyst. 13 (J) The dehydration of secondary, tertiary and benzylic alcohols could be carried out in good yield in the presence of carbodiimide and catalytic amount of CuCl. It is believed that the reaction proceeds via O-alkyl isourea intermediates. 14 (K) 2-Allyl isourea acts as a starting material for palladium-catalyzed Wittig-type allylidenation of aldehydes to give the corresponding conjugated olefins in moderate to good yields.

(A) Sawyer et al. have demonstrated the use of $KF/Al_2O_3$ and 18- Crown-6 to synthesize diaryl ethers, diarylthio ethers, and diaryl amines via $S_NAr$ type addition reaction of phenol, thiophenol, and aniline to 2-fluorobenzonitrile respectively. The optimization of the above reaction conditions led to the synthesis of compounds, which were unachievable using Ullman coupling. For example, electronically unfavorable 3-chloro benzonitrile can be condensed with 3-methylphenol to give corresponding diaryl ether in 66% yields using $KF/Al_2O_3,$ 18-Crown-6 in DMSO at 140 °C. (B) Glaser coupling reactions to generate diacetylenes using $KF/ Al_2O_3$ with $CuCl_2$ and solvent free conditions under microwave irradiation have been optimized by Kabalka et al. The use of two different alkynes, however gives a mixture of products. (C) Silveira et al. have reported the use of $KF/Al_2O_3$ for the synthesis of 3,4-dihydroisoquinolines and isoquinolines by desulfonylation of N-sulfonyltetrahydroisoquinone derivatives. Microwave irradiation (490 W) of the solid-state reaction mixture containing the substrate and base for 10–20 s gives 3,4-dihydroisoquinoline, which on increasing the time leads to the formation of corresponding isoquinoline. (D) $KF/Al_2O_3$ selectively desilylates the tert-butyldimethylsilyl protected phenol at room temperature. Acetonitrile as the solvent eliminates the need for an aqueous work up and the use of ultrasound accelerates the reaction thereby reducing reaction times. (E) Selective O-demethylation of arylalkyl ethers has also been accomplished using $KF/Al_2O_3$ and dry ethylene glycol in 3–5 h at 210–215 °C in moderate to high yields.