Showing papers in "Organic Letters in 2000"

TL;DR: A novel modification of the Staudinger ligation that generates an amide bond from an azide and a specifically functionalized phosphine should find general utility in synthetic and biological chemistry.

TL;DR: Candida antarctica lipase was shown to catalyze alcoholysis, ammoniolysis, and perhydrolysis reactions using the ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate or hexafluorophosphate as reaction media.

TL;DR: A new chemical ligation method in which a phosphinobenzenethiol is used to link a thioester and azide is used, and the product is an amide with no residual atoms.

TL;DR: Penicillin G acylase CLEAs had the same activity in the synthesis of ampicillin as cross-linked crystals of the same enzyme, but the accompanying hydrolysis of the side-chain donor was much less.

TL;DR: Palladium nanoparticles stabilized by poly(N-vinyl-2-pyrrolidone) (PVP) are efficient catalysts for the Suzuki reactions in aqueous medium, suggesting that the catalytic reaction occurs on the surface of the Pd nanoparticles.

TL;DR: A mild and highly efficient cyclization of beta-hydroxy amides to oxazolines is described using DAST and Deoxo-Fluor reagents and a one-pot protocol for the synthesis of oxazoles from beta-Hydroxy amide is presented.

TL;DR: The first general intermolecular C-N bond-forming reactions between aryl halides and amides were realized using a palladium catalyst with Xantphos as the ligand.

TL;DR: Pd(PhCN)(2)Cl(2)/P(t-Bu)(3) serves as an efficient and a versatile catalyst for room-temperature Sonogashira reactions of aryl bromides.

TL;DR: Spectral evidence supports the intermediacy of a silyliminium cation with a hydridoborate counterion formed via abstraction of a hydride from PhMe(2)SiH by B(C(6)F(5))(3) in the presence of imines.

TL;DR: In this paper, the cross-coupling of aryl boronic acids and alkanethiols mediated by copper(II) acetate and pyridine in anhydrous dimethylformamide has been used for the synthesis of the sulfide of cysteine.

TL;DR: A method for the diastereoselective synthesis of 2,4-disubstituted piperidines has been developed which enables the complete control of reaction selectivity merely by changing the order of the reaction sequence.

TL;DR: A catalytic system for the mild amination of aryl chlorides is described, which consists of a Pd(0) precursor and a dihydroimidazoline carbene ligand generated in situ from its protonated tetrafluoroborate salt.

TL;DR: Qu quantitative isolated yield and enantioselectivity of up to 95% ee was obtained and some of the Strecker adducts could be recrystallized in high recovery, yielding optically pure materials.

TL;DR: A novel diamine-catalyzed intermolecular coupling of arylboronic acids with imidazoles in dichloromethane at room temperature to give a variety of N-arylimidazole in good to excellent yields is described.

TL;DR: An efficient new process is described for the synthesis of ecteinascidin ET-743 and phthalASCidin starting from readily available cyanosafracin B.

TL;DR: As a route to accessing the potential chemical diversity of uncultivable microbes from the soil, combinatorial biosynthetic libraries were constructed by cloning large fragments of DNA isolated from soil into a Streptomyces lividans host.

TL;DR: Nitroalkanes add to cyclic and acyclic enones in an enantioselective manner in the presence of catalytic quantities of L-proline and trans-2,5-dimethylpiperazine as excess additive.

TL;DR: Curcumin is a classical phenolic chain-breaking antioxidant, donating H atoms from the phenolic groups not the CH(2) group as has been suggested.

TL;DR: Amidation of a variety of hydrocarbons with PhI=NTs catalyzed by ruthenium and manganese meso-tetrakis(pentafluorophenyl)porphyrins 1 and 2 afforded N-substituted amides in up to 92% yields with good to excellent substrate conversions.

TL;DR: In nucleosides at pH 7, 22 degrees C, the principal product is shown herein to be a spiroiminodihydantoin nucleoside, as a diastereomeric mixture, that can be characterized by NMR, ESI-MS/MS, and independent synthesis.

TL;DR: In this paper, the first macrobicyclic subunits of the all-carbon network graph were synthesized using an intramolecular Sonogashira cross-coupling sequence.

TL;DR: Two pairs of complexity-generating reactions with an essential product-substrate relationship along a synthetic pathway are demonstrated, illustrating a key element in a planning algorithm for diversity-oriented synthesis.

TL;DR: Oxime palladacycles are thermally stable complexes not sensitive to air or moisture, easily prepared from very cheap materials, which can be used as versatile and very efficient catalysts for different carbon-carbon bond-forming reactions.

TL;DR: The N-arylation of indoles, including a variety of substituted ones, has been carried out using bulky, electron-rich phosphines as the supporting ligand in combination with Pd(2)(dba)(3).

TL;DR: Modified reaction conditions have been developed to synthesize the O-methyloxime enamide side chains related to the natural products lobatamides A-F, oximidine I and II, and CJ-12,950.

TL;DR: The air, water, and highly thermally stable sulfur-containing palladacycles, mainly derived from the ortho-palladation of benzylic thioethers, are exceptional catalyst precursors for the Heck reaction.

TL;DR: Enantioselective Michael addition of nitromethane to an α,β-enone is a key step in the synthesis of (R)-baclofen.

TL;DR: Cyclopalladated compounds derived from the ortho-metalation of benzylic tert-butyl thioethers are excellent catalyst precursors for the Suzuki cross-coupling reaction of aryl bromides and chlorides with phenylboronic acid under mild reaction conditions.

TL;DR: Mild conditions, high selectivity, yield, and reaction rate, and redundancy of bromine and hydrobromic acid are some of the major advantages of the synthetic protocol.

TL;DR: The mild conditions of this novel, metal-free oxidation system for the catalytic synthesis of aldehydes and ketones--TEMPO/Oxone--has been developed and was shown to tolerate even sensitive silyl protective groups which can be cleaved in the presence of Oxone.