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A catalytic hydroxyl-directed anti-dihydroxylation of allylic and homoallylic alcohols has been developed. This operationally simple method was successfully applied to the direct anti-monodihydroxylation of allylic alcohols containing at least one distal olefinic unit. Under the catalysis of commercially available MoO2(acac)2, an array of hydroxylated dienes were successfully converted into various 1,2,3-triols using hydrogen peroxide as an environmentally benign oxidant under aerobic conditions, notably, in complete regioselectivities and in the most cases in diastereospecific pathway.

An unprecedented organocatalytic approach towards highly substituted cyclic carbonates from tri- and tetrasubstituted oxiranes and carbon dioxide has been developed. The protocol involves the use of a simple and cheap superbase under mild, additive- and metal-free conditions towards the initial formation of a less substituted carbonate product that equilibrates to a tri- or even tetrasubstituted cyclic carbonate under thermodynamic control. The latter are conveniently trapped in situ, providing overall a new domino process for synthetically elusive heterocyclic scaffolds. Control experiments provide a rationale for the observed cascade reactions, which demonstrate similarity to the well-known Payne rearrangement of epoxy alcohols.

An inexpensive, green, metal-free one-pot procedure for the dihydroxylation of alkenes is described. H2O2 and 2,2,2-trifluoroacetophenone were employed as the oxidant and organocatalyst, respectively, in this highly sustainable protocol in which a variety of homoallylic alcohols, aminoalkenes, and simple alkenes were converted into the corresponding polyalcohols in good to excellent yields. This process takes advantage of an epoxidation reaction followed by an acidic treatment in which water participates in the ring opening of the in situ prepared epoxide to lead to the desired product.

A de novo tandem benzylic oxidative dihydroxylation of α-vinyl- and α-alkenylbenzyl alcohols has been developed to give α,β-dihydroxypropiophenones (=2,3-dihydroxy-1-phenylpropan-1-ones) and α,β-dihydroxyalkyl phenones. This method was shown to be substrate-selective and specific for the oxidation of benzylic alcohols.

There is increasing evidence that cell constituents are oxidized by widely used antipsychotic drugs but until now the underlying chemistry has remained unclear. It is well known that such drugs readily undergo N-oxidation as a first key metabolic step. To gain insight into the problem, the tertiary phase 1 N-oxides of clozapine, olanzapine, quetiapine, and zotepine were synthesized, together with the N,S-dioxides of quetiapine and zotepine. These N-oxides were then subjected to well-established chemical transformations to test their oxidant properties in group VIII transition-metal-catalyzed reactions. In the osmium tetroxide catalyzed dihydroxylation of styrene or cinnamyl alcohol and in the tetrapropylammonium perruthenate catalyzed oxidation of cinnamyl alcohol, the benzepine N-oxides could be used as replacements for the standard oxidant, N-methylmorpholine N-oxide (NMO) with varying degrees of efficiency. From a chemical point of view, clozapine N-oxide displayed a comparable oxidation power to NMO, characterizing the benzepines as oxygen carriers. Moreover, quetiapine was found to be an excellent double oxygen acceptor, undergoing initial N-oxidation and subsequent S-oxidation. It is therefore worthwhile considering whether oxidative damage to the human body might be related to the potential redox properties of common antipsychotic drugs. Georg Thieme Verlag Stuttgart ? New York.

Polymer supported vanadium complexes (denoted as c-PMA n -V) were prepared by the complexation of vanadium ions onto a cross linked polyacrylate. c PMA n -V can catalyze the oxidative cleavage of olefins with a large excess of t-butyl hydroperoxide (TBHP) or bishydroxylation of olefins with 4 eq. of TBHP. Graphical Abstract: [Figure not available: see fulltext.].

Effective hydrolysis of epoxides and aziridines was conducted by heating them in water at 60 or 100 °C. Other types of nucleophile such as amines, sodium azide, and thiophenol could also efficiently open epoxides and aziridines in hot water. It was proposed that hot water acted as a modest acid catalyst, reactant, and solvent in the hydrolysis reactions.

Details of a study on the intramolecular bis-silylation of terminal alkenes promoted by a palladium-tert-alkyl isocyanide catalyst are described. With a disilanyl ether derived from a homoallylic alcohol, intramolecular regioselective addition of the Si-Si linkage to the C=C bond took place to furnish an exo-ring closure product, i.e., 1,2-oxasilolane. The bis-silylation of alkenes having substituents α to the C=C bond gave trans-3,4-disubstituted oxasilolanes, while substitution β to the C=C bond favored cis-3,5-disubstituted oxasilolanes. The stereoselectivity trends are formulated as arising from a preference for a chairlike transition state over a boatlike one. A substituent, either a or β to the C=C bond, prefers the equatorial position in a chairlike transition state. The 1,2-oxasilolanes thus produced stereoselectively were oxidatively converted to the corresponding 1,2,4-triols. The present methodology for the synthesis of 1,2,4-triols was successfully extended to the stereoselective synthesis of 1,2,4,5,7- and 1,2,4,6,7-pentaols through a sequence of intramolecular bis-silylations. The bis-silylation was also performed with alkenes linked to disilanyl groups through a three-carbon chain and through an amide linkage. Stereoselections analogous to those of the ether substrates were observed. Alkenes tethered to disilanyl groups through chains of two atoms underwent similar intramolecular bissilylation. In conclusion, the intramolecular bis-silylation of C=C bonds followed by oxidation constitutes a new synthetic transformation equivalent to the stereoselective dihydroxylation of olefins.

2,3-Epoxyalcohols react with paraformaldehyde and either cesium carbonate or potassium carbonate/phase-transfer catalyst in polar, aprotic solvents to give excellent yields of 4-(1-hydroxyalkyl)-1,3-dioxolanes, with inversion at C-2.