[Au]-Catalyzed Cyclization of Propargyl-Tethered Ene-Amides: Substrate-Dependent Access to Tetrasubstituted Pyrroles, Aminophenols, and Dihydropyridines

[Au]-catalyzed and substrate-dependent intramolecular cyclization of sulfonyl ene-amides with a pendant propargyl group afford tetrasubstituted pyrroles, o-aminophenols, or 1,6-dihydropyridine carbaldehydes. While the pyrroles and aminophenols are formed when the propargylic alkyne is terminal, dihydropyridines are formed when internal alkyne is present. Internal alkyne substrates with 2-thienyl and 3-thienyl groups give different types of dihydropyridines. The dihydropyridines so obtained can be readily converted to nicotinaldehydes with concomitant sulfonyl migration upon heating in xylene.

Stereoselective synthesis of enamino ketones through an aza-Michael/hydrolysis cascade reaction

Highly functionalized (Z)-β-enamino ketones have been prepared from readily available 3,4-dihydroisoquinoline imines and ynones through an aza-Michael/hydrolysis cascade reaction.

N-Propargylic β-enaminocarbonyls: powerful and versatile building blocks in organic synthesis

Nitrogen-containing heterocyclic compounds are not only prevalent in an extensive number of natural products and synthetic pharmaceuticals but are also used as building blocks in organic synthesis.

Gold-catalyzed intramolecular cyclization/condensation sequence: synthesis of 1,2-dihydro[c][2,7]naphthyridines

An efficient gold-catalyzed protocol for the construction of 1,2-dihydro[c][2,7]naphthyridines from 2-aminophenyl prop-2-yn-1-yl enaminones has been developed. In this organic transformation new C–C and C–N bonds were formedvia6-endo-dig cyclization and good to excellent yields were obtained in one-pot synthesis.

Base-catalyzed cascade synthesis of 2,3-dihydrofuro[2,3-b]pyridines and 2,3-dihydro-1H-pyrrolo[2,3-b]pyridines from N-propargylic β-enaminones

A novel protocol to prepare dihydrofuropyridine and dihydropyrrolopyridine derivatives from KOH-catalyzed reactions between N-propargylic β-enaminones and arylaldehydes or N-sulfonyl imines has been developed.

Gold(iii)-catalyzed synthesis of aroylbenzo[b]oxepin-3-ones from ortho-O-propargyl-1-one substituted arylaldehydes

An efficient gold-catalyzed intramolecular cyclization of ortho-O-propargyl-1-one substituted arylaldehydes has been achieved for the generation of substituted aroylbenzo[b]oxepin-3-one derivatives in moderate to good yields. This synthetic transformation proceeds via gold-catalysed oxidation of the internal alkyne moiety followed by an intramolecular condensation leading to seven-membered oxacycles.

Base-promoted intramolecular cyclization of N-alkyl, N-propargylic β-enaminones for the synthesis of polysubstituted pyrroles

An efficient, mild, metal-free, base-mediated intramolecular cyclization of N-alkyl, N-propargylic β-enaminones has been realized for the generation of polysubstituted pyrrole derivatives.

Facile synthesis of heavily-substituted alkynylpyridines via a Sonogashira approach

A robust synthesis of highly-substituted alkynylpyridines via a Sonogashira approach is described, providing a library of functionalized pyridines for biological studies.

Base-mediated regiospecific cascade synthesis of N-(2-pyridyl)pyrroles from N-propargylic β-enaminones

Two birds with one stone: two classical heterocycles, pyrrole and pyridine, were simultaneously installed from one acyclic enaminone precursor for the preparation of N-(2-pyridyl)pyrroles.

New page to access pyridine derivatives: synthesis from N-propargylamines

The pyridine is one of the simplest, yet most important N-heterocycles.

Reaction of β-enaminones and acetylene dicarboxylates: synthesis of substituted 1,2-dihydropyridinones

Synthesis of dihydropyridinones was achieved by reaction of β-enaminones with acetylene dicarboxylates without using transition metal/catalyst.