Regioselective Benzylation Research Articles

Regioselective Benzylation of an Indazolyl-substituted Pyrazole under the Influence of Inorganic Solid Supported Bases

The benzylation of an indazolyl-substituted pyrazole under the influence of KOH–AI2O3, KF–AI2O3 and CsF–AI2O3 is investigated.

Regioselective Benzylation of an Indazolyl-substituted Pyrazole under the Influence of Inorganic Solid Supported Bases

The benzylation of an indazolyl-substituted pyrazole under the influence of KOH–Al2O3, KF–Al2O3 and CsF–Al2O3 is investigated.

Synthesis of Glycosyl Acceptors by Regioselective Benzylations of a 2-Deoxy-2-phthalimido-D-glucoside.

Abstract The direct regioselective benzylation of p-methoxyphenyl 2-deoxy-2-phthalimido-β-D-glucopyranoside (1) with benzyl bromide under basic conditions gives 4,6-di-O-benzyl (2a), 4-O-benzyl (3a) and 6-O -benzyl-2-deoxy-2-phthalimido-β-D-glucopyranoside 4a. When the benzylation was performed in the presence of di-n-butyltin oxide, p-methoxyphenyl 4,6-di-O-benzyl-2-deoxy-2-phthalimido-β-D-glucopyranoside 5 was obtained in high yield. This constitutes a new and efficient one-pot procedure for the synthesis of the glycosyl acceptor 5.

Alkylation of Thiophenes and Preparation of Benzothiophenes Using Modified Montmorillonite Clay Catalysts

Abstract Regioselective benzylation of thiophene and benzothiophene using benzyl chloride and a ZnCl2-promoted montmorillonite catalyst is described. An improved process for the cyclization of (arylthio)acetaldehyde dialkyl acetals to benzothiophenes using the same catalyst is also documented.

Synthesis of 1,4,6‐tri‐O‐benzyl myo‐inositol—A key intermediate to myo‐inositol‐1,2,5‐O‐trisphosphate

AbstractA new synthetic approach to 1,4,6‐tri‐O‐benzyl myo‐inositol was described on the basis of the regioselective benzylation of 1,2‐O‐iaopropylidene‐4,6‐di‐O‐benzyl myo‐inositol, subsequent acid hydrolysis, phosphorylation with tetrabenazylpyrophosphate and appropriate deprotection.

Alkylation of Thiophenes and Preparation of Benzothiophenes Using Modified Montmorillonite Clay Catalysts

Abstract Regioselective benzylation of thiophene and benzothiophene using benzyl chloride and a ZnCl2-promoted montmorillonite catalyst is described. An improved process for the cyclization of (arylthio)acetaldehyde dialkyl acetals to benzothiophenes using the same catalyst is also documented.

The regioselectivity of tributyltin ether-mediated benzylation of 1,6-anhydro-β- d-hexoipyranoses

The benzylation of 1,6-anhydro-β- d-galactopyranose and the manno, allo, altro, gulo, talo, gluco, and ido isomers, using bis(tributyltin) oxide and N-methylimidazole, tetrabutylammonium bromide, tetrabutylammonium iodide, or tetrabutylammonium fluoride as catalyst, has been studied. The results confirm the importance of the catalyst in the benzylation reactions and indicate that the presence of a cis-axial hydroxyl group seems to be necessary for regioselective benzylation.

Preparations and reactions of (Z)-3-arylidene-6-arylmethyl-2,5-piperazinediones having highly oxygenated benzene rings.

A simple and efficient synthesis of a variety of (Z) -3-arylidene-6-arylmethyl-2, 5-piperazine-diones 10 having highly oxygenated benzene rings, and regioselective benzylation at position 4 are described.

Synthesis of 3,6-di- O-acetyl-2-deoxy-2-phthalimido-4- O-(2,3,4,6-tetra- O-acetyl-β- d-galactopyranosyl)-β- d-glucopyranosyl chloride

A lactosaminyl donor, 3,6-di- O-acetyl-2-deoxy-2-phthalimido-4- O-(2,3,4,6-tetra- O-acetyl-β- d-galactopyranosyl)-β- d- glucopyranosyl chloride, was synthesized in 10 steps, starting from 1,3,4,6-tetra- O-acetyl-2-deoxy-2-phthalimido-β- d-glucopyranose. Benzyl 3,6-di- O-benzyl-2-deoxy-2-phthalimido-β- d-glucopyranoside was prepared by regioselective benzylation at the primary hydroxyl group by the stannyl method, and was used as a key intermediate. ▪