A mild, one-pot preparation of 1,3,4-oxadiazoles

A mild and efficient one-pot protocol for the synthesis of 1,3,4-oxadiazoles from carboxylic acids and acylhydrazides was developed. Diacylhydrazide formation via HATU coupling followed by addition of Burgess reagent afforded the corresponding 1,3,4-oxadiazoles in 63-96% yields at room temperature. The reaction conditions are tolerant of a variety of functional groups, including esters, nitriles, alkynes, olefins, alkyl halides, phenols, carbamates and sulfonamides.     

A one-pot preparation of 1,3-disubstituted azetidines

A straightforward synthesis of 1,3-disubstituted azetidines has been accomplished via the alkylation of a primary amine with the bis-triflate of a 2-substituted-1,3-propanediol species. This transformation is carried out in one reaction vessel, and elimination of the alkylating reagent is generally not a major byproduct. The scope of this methodology has been investigated using a variety 2-substituted-1,3-propanediols and amine nucleophiles.     

A one-pot preparation of N-2-mercaptobenzoyl-amino amides

The HIV-1 nucleocapsid (NCp7), structurally defined by zinc-binding domains, participates in crucial stages of the HIV-1 lifecycle and is mutationally nonpermissive, making it an attractive anti-HIV target. Mode of action studies have shown that the secondary structure and activity of NCp7 can be disrupted by acyl transfer from N-2-mercaptobenzoyl-amino amides. We have developed an improved one-pot reaction that affords N-2-mercaptobenzoyl-amino acids on multi-gram scales. This synthetic route allows for rapid modular construction and has greatly expanded the scope of easily accessible potential NCp7 inhibitors.     

A mild and efficient one-pot synthesis of 2-dihydroimidazoles from aldehydes

The reactions of various aldehydes and 1,2-diamines followed by NXS treatment proceed at 0 °C-rt to give the corresponding dihydroimidazoles in high yields. The reaction is mild, and many functional groups such as halogens, nitriles, and esters can exist.     

A new mild method for the one-pot synthesis of pyridines

Polysubstituted pyridines are prepared in good yield and with total regiocontrol by the one-pot reaction of an alkynone, 1,3-dicarbonyl compound and ammonium acetate in alcoholic solvents. This new three-component heteroannulation reaction proceeds under mild conditions in the absence of an additional acid catalyst and has been used in the synthesis of dimethyl sulfomycinamate, the acidic methanolysis degradation product of the sulfomycin family of thiopeptide antibiotics.     

A simple one-pot preparation of diazoacetoacetate derivatives from aldehydes

Diazoacetoacetate derivatives can be simply and efficiently prepared from aldehydes in a one-pot process involving initial DBU-promoted "aldol" condensation with ethyl diazoacetate followed by in situ oxidation with IBX. Aryl, alkyl, and unsaturated aldehydes are all viable substrates.     

A versatile and general one-pot method for synthesizing bis-spiroketal motifs

[reaction: see text] A versatile and general method for the biomimetic construction of [5,5,5]- and [6,5,6]-bis-spiroketals, starting from easily accessible furan nuclei, by means of a powerful one-pot singlet oxygen-mediated cascade sequence is reported.     

A mild, one-pot synthesis of disubstituted benzimidazoles from 2-nitroanilines

A one-pot synthesis of disubstituted benzimidazoles from 2-nitroanilines is described. Hydrogenation of N-substituted 2-nitroanilines with palladium on carbon as catalyst in the presence of trimethyl orthoformate and catalytic pyridinium p-toluenesulfonate (PPTS) at room temperature provided good to excellent yields of the corresponding disubstituted benzimidazoles.     

Facile deallylation protocols for the preparation of N-unsubstituted triazoles and tetrazoles

Two facile deallylation protocols have been developed for the preparation of N-unsubstituted triazoles and tetrazoles. The first protocol is a direct deallylation using a combination of a catalytic amount of nickel complex, NiCl2(dppe), and a stoichiometric amount of Grignard reagent, tBuMgCl. The second protocol is a stepwise deallylation through consecutive reactions of isomerization and ozonolysis. The isomerization from N-allylazoles to N-vinylazoles is catalyzed by a ruthenium complex, HRuCl(CO)(PPh3)3, and the following ozonolysis of the derived N-vinyl intermediates affords N-unsubstituted azoles. These protocols can be used complementarily depending on the type of functional groups in the parent allylated azoles.     

A new and general one-pot synthesis of propargyl alcohols from esters

Intermediates easily prepared by partial reduction of various esters with LDBBA as a reducing agent smoothly react with lithium acetylides to give propargyl alcohols, without isolation of partial reduction intermediates, in good yields (73-83%).     

A facile one-pot preparation of potassium hydroxyaryl- and (hydroxyalkyl)aryltrifluoroborates

Potassium hydroxyaryl- and (hydroxyalkyl)aryltrifluoroborates have been prepared in a simple one-pot process from the corresponding hydroxy-substituted aryl halides in 51-98% yields through an in situ protection of the free hydroxyl group with t-BuLi. Also, we successfully performed a microwave-promoted Suzuki-Miyaura cross-coupling reaction of these substrates with aryl- and alkenyl bromides in the presence of 0.5 mol % of Pd(OAc)2 catalyst without ligands.     

A general and mild Ullmann-type synthesis of diaryl ethers

[reaction: see text] An efficient method for the synthesis of diaryl ethers under particularly mild conditions is described. Inexpensive ligands were found to greatly accelerate the Ullmann-type coupling of aryl bromides or iodides with phenols. A series of diaryl ethers were obtained with excellent yields in acetonitrile in the presence of Cs(2)CO(3) and catalytic copper(I) oxide. The reaction tolerates substrates with unfavorable substitution patterns, such as sterically hindered coupling partners or electron-rich aryl halides.     

A high yielding one-pot method for the preparation of salen ligands

Phenols are converted to salicylaldehydes with paraformaldehyde, MgCl₂-Et₃N in THF, and subsequently treated with (+)-(R,R)-1,2-diammoniumcyclohexane mono-(+)-tartrate salt affording the corresponding salen ligands in high yields. The reactions are conveniently carried out as a one-pot procedure.     

Indium-mediated mild and efficient one-pot synthesis of alkyl phenyl selenides

A mild and convenient one-pot process for synthesizing alkyl phenyl selenides is developed using indium metal. The reaction shows the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides.     

A new, mild preparation of sulfonyl chlorides

A new method was developed for the preparation of sulfonyl chlorides from sulfonic acids under neutral conditions using 2,4,6-trichloro-1,3,5-triazine as chlorinating agent.     

A DMAP-catalyzed mild and efficient synthesis of 1,2-dihydroquinazolines via a one-pot three-component protocol

An efficient and simple method for the synthesis of 1,2-dihydroquinazolines catalyzed by 4-(N,N-dimethylamino)pyridine (DMAP) from readily available aromatic or heteroaromatic aldehydes, 2-aminobenzophenone, and ammonium acetate under mild conditions is described. The scope and limitations of the method are discussed.     

A one-pot three-component reaction for the preparation of highly functionalized tryptamines

We have developed a general one-pot method to provide highly functionalized tryptamine derivatives, via a Fischer indole type pathway. In this article, we demonstrate optimal conditions for a one-pot indole synthesis, allowing for the synthesis of a broad scope of 2-methyl tryptamine derivatives and a precursor for the synthesis of the core structure of some akuammiline alkaloids. Additionally, further modification of the indole products is described.