Lewis acid catalyzed acylation reactions: scope and limitations
作者:Kusum L Chandra、P Saravanan、Rajesh K Singh、Vinod K Singh
DOI:10.1016/s0040-4020(01)01229-7
日期:2002.2
Acylation of alcohols, thiols, and sugars were studied with a variety of Lewis acids, and it was found that Cu- and Sn(OTf)2 are very efficient in catalyzing the reaction under mild conditions. Among these two catalysts, Cu(OTf)2 was preferred because of its lower cost and relatively higher yield of the acylated product. The reaction was studied in several solvents, but CH2Cl2 was preferred. It was
A general and practical process for the conversion of prochiral ketones into the corresponding chiral acetates has been realized. An iron carbonyl complex is reported to catalyze the hydrogenation–dehydrogenation–hydrogenation of prochiral ketones. By merging the iron‐catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones
Cyclic ethers such as tetrahydrofuran or tetrahydropyran were easily cleaved at room temperature by sulfuricacid - aceticanhydride providing the corresponding diacetoxyalkanes in good yield. The ring opening was applicable to saturated cyclic ethers, regardless of the presence of substituent groups.
Double asymmetric hydrogenation of conjugated dienes: a self-breeding chirality route for <i>C</i><sub>2</sub> symmetric 1,4-diols
作者:Félix León、Javier Francos、Joaquín López-Serrano、Sergio E. García-Garrido、Victorio Cadierno、Antonio Pizzano
DOI:10.1039/c8cc09391a
日期:——
The synthesis and doubleasymmetrichydrogenation of (Z,Z)-1,3-diene-1,4-diyl diacetates is described. In this reaction C2/meso ratios up to 85 : 15 and enantioselectivities up to 97% ee have been achieved. As the hydrogenation products can be converted into chiral 1,4-diols, key starting materials for the preparation of the best catalysts used, this catalytic system enables a self-breeding chirality
Borylation of Stable C(sp3)–O Bonds of Alkyl Esters over Supported Au Catalysts
作者:Masafumi Doi、Hiroki Miura、Tetsuya Shishido
DOI:10.1021/acs.orglett.4c00225
日期:2024.4.19
that supported gold catalysts efficiently promote the borylation of stableC(sp3)–Obonds of alkylesters. The use of a disilane as an electron source and gold nanoparticles as a single-electron transfer catalyst is the key to generating alkyl radicals via the homolysis of stableC(sp3)–Obonds, thereby enabling cross-coupling between bis(pinacolato)diboron and linear and cyclic alkylesters to afford