A Sc(OTf)3-catalyzed reaction of vinyl azides with donor–acceptor cyclopropanes affords highly functionalized azidocyclopentanes in a diastereoselective fashion. The resulting azidocyclopentanes could be transformed into various cyclic scaffolds.
The first enantioselective decarboxylative aldol addition with α-amido-substituted malonic acid half oxyesters (MAHOs) is described. The combined use of a newly designed bifunctional sulfonamide catalyst with pentafluorobenzoic acid as an additive afforded the β-hydroxy-α-amino acid derivatives in moderate to high yields and with high enantioselectivities.
A palladium-catalyzed three-component coupling reaction of 2-fluoroallylic acetates with phenols, and imides is disclosed. The reaction was effectively catalyzed by [Pd(C3H5)Cl]2/DPPF in the presence of Cs2CO3, and phenols and imides were introduced onto the allyl unit through the C–F bond activation. Furthermore, the reaction proceeds with both high regioselectivity and high Z-selectivity.
A variety of N-tosylaziridines undergo smoothly ring opening with aromatic amines using a catalytic amount of lithium perchlorate in acetonitrile at ambient temperature to afford the corresponding 1,2-diamines in excellent yields.
Carbohydrate acetonides were chemoselectively cleaved to the corresponding diols by using environmentally benign phosphomolybdic acid (H3PMo12O40) supported on silica gel (PMA-SiO2) at ambient temperature in a short span of 5-7 minutes in acetonitrile. Acid-labile protective groups such as THP, TBS, TBDPS, MOM, OMe and PMB were found to be stable under the reaction conditions.
A novel one pot condensation of an aldehyde, β-ketoester and urea has been performed using TMSI in acetonitrile for the first time at room temperature affording dihydropyrimidinones in excellent yields.
Epoxides react smoothly with potassium thiocyanate in the presence of 5 mol% of indium tribromide under mild and convenient reaction conditions to afford the corresponding thiiranes in high yields. This method is compatible with a wide range of protecting groups and functional groups such as alkenes, alkynes, esters, THP, TBDMS, and PMB ethers present in the molecule.
Indoles react smoothly with terminal epoxides in the presence of catalytic amount of InCl3 under mild conditions to afford the corresponding 3-alkyl indole derivatives in high yields with high regioselectivity.
Scandium triflate catalyzes efficiently the allylation reactions of acetals and gem-diacetates with allyltrimethylsilane at ambient temperature to afford the corresponding homoallyl ethers and acetates in high yields. Also it is found to be effective for the direct formation of homoallyl ethers from aldehydes and allylsilane in presence of trimethylorthoformate.
α-Aminophosphonates are synthesized by three component condensation of aldehydes, amines and diethyl phosphite using montmorillonite KSF under microwave irradiation in solvent-free conditions to afford enhanced yields and reduced reaction times compared to conventional methods.