Showing papers in "Tetrahedron Letters in 1998"

TL;DR: In this article, a new method of arylating NH and OH containing compounds at room temperature with phenylboronic acids and cupric acetate in the presence of a tertiary amine promoter is described.

TL;DR: A new aryl/heteroaryl CN bond cross-coupling reaction via the aRYlboronic acid/cupric acetate arylation of NH containing heteroarenes has been discovered.

TL;DR: In this paper, the copper-II-promoted coupling of arylboronic acids and phenols has been applied to arylation of phenolic amino acids, which has been used for the synthesis of thyroxine.

TL;DR: Bicyclic nucleoside analogues with a fixed N-type conformation, 2′-O,4′-C-methyleneuridine and -cytidine, were incorporated into oligonucleotides, and the binding efficiency of the modified oligon nucleotides to the complementary DNA and RNA as well as the CD spectra of themodified DNA-DNA and modified DNA-RNA duplexes were studied.

TL;DR: Fosmidomycin inhibited 1-deoxy-d-xylulose 5-phosphate reductoisomerase pathway for terpenoid biosynthesis with IC50 of 8.2 nM.

TL;DR: A three-component condensation reaction between 2-aminopyridine, an aldehyde and an isonitrile catalyzed by scandium triflate affords derivatives of 3-aminoimidazo[1,2-a]pyridine; aminopyrazine reacts similarly.

TL;DR: In this paper, a triarylamines can be readily prepared in excellent yields by palladium-catalyzed cross-coupling reaction of aryl halides and diarylamines.

TL;DR: In this paper, a PdP(t-Bu)3 catalyst system has been used for the amination of N-(hetero)aryl halides with unprotected piperazine.

TL;DR: In this article, a variety of ketones have been prepared by a palladium-catalyzed reaction of ethanethiol esters with organozinc reagents, including esters, ketones, aromatic halides and aldehydes.

TL;DR: The nucleophilic cyclopropanation of C60 with a second generation bis(polyamide)-malonate dendrimer and the subsequent deprotection of the terminal t-butyl groups provides a dendro[60]fullerene with 18 carboxylic groups in the periphery as mentioned in this paper.

TL;DR: In this article, the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by substituted phenols leads to a vinyltriphenylPHosphonium salt, which undergoes aromatic electrophilic substitution reaction with the phenolate conjugate base to produce 4-carboxymethylcoumarins in fairly high yields.

TL;DR: The chiral quaternary ammonium salt as mentioned in this paper serves as phase transfer catalyst for the enantioselective conversion of the glycine derivative 2 to a variety of cyclic and acyclic chiral α-amino acids with enanti-lectivities as high as 200:1 in alkylation and Michael addition reactions.

TL;DR: A catalytic amount of an oxalate/oxalic acid buffer strongly enhances the catalytic properties of Mn-tmtacn complexes for epoxidation reactions with H 2 O 2.

TL;DR: In this article, the synthesis of tetrathiacalix[4]arene was achieved by detertiobutylation of p-tert-butyltetrathiatectetrathiaalix [4]-arene.

TL;DR: In this article, a novel CrO 3 catalyzed oxidation of primary alcohols to the carboxylic acids was reported, and the oxidation proceeds smoothly with only 1−2 mol % of CrO3 and 2.5 equivalents of H 5 IO 6 in wet MeCN.

TL;DR: In this paper, a combination of Pd(OAc)2/pyridine/MS3A catalyzes the aerobic oxidation of various benzylic alcohols into corresponding aldehydes and ketones in good yield.

TL;DR: The deblocking reagent, which contains 1-methylpyrrolidine, hexamethyleneimine and HOBt in a one to one mixture of NMP and DMSO, realized the preparation of peptide thioesters by an Fmoc solid-phase method in a yield equivalent to that obtained by a Boc solid phase method.

TL;DR: 1-Deoxy-d -xylulose 5-phosphate is biotransformed to 2-C-methyl- d -erythritol 4-ph phosphate in a single step in the presence of NADPH by a new recombinant enzyme named 1-deoxy- d-xyluminescence reductoisomerase purified from Escherichia coli.

TL;DR: In this paper, the four methylene birdge of calix[4]arenes are replaced by sulfide linkages, and they were selectively oxidized to sulfinyl- or sulfonylcalix[ 4]arene under mild conditions with control of the stoichiometry of the oxidant.

TL;DR: In this article, a wide range of tertiary amides with 2 molar equivalents of diphenylsilane was promoted by 0.1 mol% of RhH(CO)(PPh 3 ) 3 at room temperature.

TL;DR: In this paper, eight chiral Schiff-base ligands were prepared from (S)-tert.-leucinol and four chiral, racemic salicylic aldehydes.

TL;DR: In this article, a robust linear approach allowing selective formation of the desired [2.2.1]bicyclo LNA nucleosides via a tricyclic nucleoside intermediate is introduced.

TL;DR: Equisetin and a novel opposite stereochemical homolog, phomasetin, are isolated from Fusarium heterosporum and a Phoma sp.

TL;DR: In this article, the enantioselective epoxidation of α,β-unsaturated ketones using Cinchona alkaloid-derived quaternary ammonium phase-transfer catalysts bearing an N-anthracenylmethyl function is presented.

TL;DR: The swelling abilities of many solvents were examined volumetrically on Wang, Merrifield, TentaGel S RAM, MBHA, Trityl, and Rink amide resins as discussed by the authors.

TL;DR: TaCl 5 and TaCl 5 -Silica gel have been effectively used as Lewis acid catalysts for acetylation of alcohols as discussed by the authors, and they have been used for kinetic resolution of 2° alcohols albeit in low ees.

TL;DR: In this paper, alcohols and phenols were efficiently acylated with acetic anhydride without solvent over zeolite HSZ-360, and the catalyst can be reused with no activity loss.

TL;DR: In this paper, a series of new variants of Dde, substituted at the exocyclic alkene position, have been developed and their application in solid phase peptide synthesis assessed.

TL;DR: An organozinc species RXZnCH 2 I generated by reacting Zn(CH 2I) 2 with RXH was found to be an efficient reagent for the cyclopropanation of olefins at room temperature as discussed by the authors.

TL;DR: In this paper, the reaction of 2-cyclohexenones 1a-d with aqueous formaldehyde, catalyzed by DMAP in THF, affords the corresponding 2-(hydroxymethyl)-2-cycloenones 2a-D in good yields.