Magnesium Chloride–Catalyzed Thiolysis of Epoxides: Synthesis of β-hydroxy Sulfides

A mild and convenient ring opening of epoxides with thiophenol and its derivatives takes place at room temperature in the presence of magnesium chloride as catalyst to afford the corresponding β-hydroxy sulfides along with minor amounts of 2-chlorocycloalkanols in good yields. When the crude reaction mixtures are treated with aqueous sodium hydroxide solution, pure 2-arlythiocycloalkanols are obtained in good yields.     

Potassium Dodecatungstocobaltate Trihydrate (K5CoW12O40 · 3H2O) as an Efficient Catalyst for Aminolysis of Epoxides

Abstract

Aminolysis of epoxides using various amines was catalyzed with potassium dodecatungstocobaltate trihydrate in a convenient and efficient method with good selectivities.     

Enantioselective synthesis of decarestrictine J

An efficient total synthesis of decarestrictine J has been achieved using ring-closing metathesis and Yamaguchi esterification as key steps. The stereogenic centres were generated by means of iterative hydrolytic kinetic resolution (HKR) of racemic epoxides.     

A highly regio- and chemoselective synthesis of vicinal bromohydrins by ring opening of terminal epoxides with dibromoborane-dimethyl sulfide

Dibromoborane-dimethyl sulfide (BHBr₂-SMe₂) displays high degrees of chemo- and regioselectivity during the brominative cleavage of the epoxy group into vicinal bromohydrins in the presence of alkene, alkyne, allene, ether, acetal and acetonide, besides its hydroborating ability. Several reducible functional groups, such as chloride, aldehyde, ketone, azide, ester, nitrile and tert-amino ester, have been successfully accommodated during the epoxide opening process.     

Epoxide opening with amino acids: improved synthesis of hydroxyethylamine dipeptide isosteres

The amino acid opening of epoxides, catalyzed by calcium trifluoromethanesulfonate with short reaction times is described. The method can be used in a straightforward route for the preparation of hydroxyethylamine dipeptide isosteres.     

Synthesis of highly modular bis(oxazoline) ligands by Suzuki cross-coupling and evaluation as catalytic ligands

New bis(oxazoline) ligands (BOXs) containing biaryl substitutents at the C-4 position and H or CH₂OR substituents at the C-5 position have been synthesized using Suzuki cross-coupling as the main tool for structural diversity. Copper, zinc, and palladium complexes of the prepared BOXs have been evaluated in the following catalytic asymmetric processes: Acylation with kinetic resolution of trans-1,2-cyclohexanediol (Cu), enantioselective Friedel-Crafts alkylation of indole (Zn), and enantioselective alkylation of 3-acetoxy-1,3-diphenylpropene (Pd).     

Novel dihydrazone based polymers for electrophotography

The novel family of hole-transporting polymers containing hydrazone moieties is reported. The polymers were prepared in polyaddition reaction of dihydrazone-containing diepoxides with bifunctional nucleophilic linking agents in the presence of catalyst triethylamine. Obtained polymers were found to constitute novel polymeric hole transporting materials characterized by differential scanning calorimetry and time of flight method. The highest hole drift mobility in the newly synthesized polymers exceed 10⁻⁵ cm² V⁻¹ s⁻¹ at an electric field of 10⁶ V cm⁻¹.     

Synthesis of β‐Chlorohydrins in Water

2,4,6‐Trichloro‐1,3,5‐triazine (TCT, cyanuric chloride) was found to mediate the regio‐ and stereoselective ring opening of epoxides in H₂O in the presence of morpholine at room temperature to afford the corresponding β‐chlorohydrins in excellent yields (Table). The transformation is very simple, fast, efficient, and ecologically beneficial.     

An easy way for constructing hard-to-make epoxides employing HOF·CH3CN

HOF·CH₃CN, a very efficient oxygen transfer agent, was reacted with various types of difficult-to-epoxidize olefins. All products were obtained in a single-step, fast and high yield reaction.     

Boron trifluoride-induced reactions of phenylglycidyl ethers: a convenient synthesis of enantiopure, stereodefined fluorohydrins

Ring-opening hydrofluorination of enantiomerically pure (2S,3S)-3-arylglycidyl ethers (aryl = phenyl, 4-trifluoromethylphenyl) by boron trifluoride-diethyl ether under mild conditions provides β-fluoro alcohols in good yield in a stereospecific manner with complete regiocontrol.