Chao-Guo Yan

Facile synthesis of dispirooxindole-fused heterocycles via domino 1,4-dipolar addition and Diels-Alder reaction of in situ generated Huisgen 1,4-dipoles.

A facile synthetic protocol was developed for the efficient synthesis of complex dispirooxindole-fused heterocycles via a three-component reaction. The key strategies involve a domino 1,4-dipolar addition and Diels-Alder reaction of the in situ generated Huisgen 1,4-dipoles from the addition reaction of 4-dimethylaminopyridine with acetylenedicarboxylate to 3-phenacylideneoxindole.

Synthesis of 3,4-Dihydropyridin-2(1H)-ones and 3,4-Dihydro-2H-pyrans via Four-Component Reactions of Aromatic Aldehydes, Cyclic 1,3-Carbonyls, Arylamines, and Dimethyl Acetylenedicarboxylate

A protocol has been developed for the efficient synthesis of structurally diverse 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via four-component reactions of arylamines, acetylenedicarboxylate, aromatic aldehydes and cyclic 1,3-diketones. The selective formation of the very different pyridinone or pyran derivatives depends on the structure of cyclic 1,3-diketone. The key steps are proposed to involve Michael addition of the enamino ester formed in situ from the reaction of arylamine with dimethyl acetylenedicarboxylate to arylidine cyclic 1,3-diketones.

Synthesis of Functionalized 2-Aminohydropyridines and 2-Pyridinones via Domino Reactions of Arylamines, Methyl Propiolate, Aromatic Aldehydes, and Substituted Acetonitriles

An efficient and practical synthetic method for the functionalized 2-amino hydropyridines and 2-pyridinones was successfully developed via the domino reactions of arylamines, methyl propiolate, aromatic aldehydes and the substituted acetonitriles with triethylamine as base catalyst. Reactions involving malononitrile and cyanoacetamide gave exclusively the 2-aminohydropyridines. On the other hand ethyl cyanoacetate resulted in the 2-pyridinones as main products.

Domino Reactions of Vinyl Malononitriles with 3-Phenacylideneoxindoles for Efficient Synthesis of Functionalized Spirocyclic Oxindoles

The reactions of vinyl malononitriles with 3-phenacylideneoxindoles in ethanol in the presence of DBU as base resulted in the functionalized spirocyclic oxindoles through the domino Michael addition and intramolecular nucleophilic addition to cyano group. On the other hand, the similar reaction in the presence of piperidine as base afforded the simple Michael addition products in good yields. The stereochemistry of the spirooxindoles was established with (1)H NMR data and single crystal structures.

Unprecedented formation of 2-oxaspiro[bicyclo[2.2.1]heptane-6,3′-indoline] derivatives from reaction of 3-phenacyalideneoxindole with malononitrile or ethyl cyanoacetate

The reaction of malononitrile or ethyl cyanoacetate with two molecules of 3-phencylideneoxindoles in ethanol in the presence of piperidine at room temperature afforded novel 7-(1-benzyl-2-oxoindolin-3-yl)-2′-oxo-2-oxaspiro[bicyclo[2.2.1]heptane-6,3′-indoline] derivatives in good yields. Under similar reaction conditions, the reaction of cyanoacetamide with 3-phencylideneoxindoles resulted in polysubstituted 4-(2-oxoindolin-3-yl)-2-oxopyrrolidines. The stereochemistry of the reaction was well established by data from 1H NMR spectra and single crystal structures and a plausible reaction mechanism is rationally proposed.

Synthesis of polyfunctionalized acrylates via one-pot reactions of arylamines, methyl propiolate, aromatic aldehydes, and active methylene compounds.

An efficient synthetic method for the densely substituted 3-arylaminoacrylates was successfully developed via the one-pot reaction of arylamines, methyl propiolate, aromatic aldehydes, and active methylene compounds such as pivaloylacetonitrile, 1,3-cyclopentanedione, and 4-hydroxycoumarin. The key step of the reaction was believed to involve the formation of a β-enamino ester and a sequential Michael addition to the in situ formed arylidene dicarbonyl compound.

Dicopper complex of p-tert -butylcalix8arene bearing acylhydrazone pendant domains

A dicopper complex of p-tert-butylcalix8arene bearing eight salicylaldehyde acylhydrazone domains was prepared and its single crystal structure determined, in which only four acylhydrazone domains act as monoanionic tridentate planar chelators to coordinate to two copper ions.

Syntheses and structures of Mn(II), Co(II), and Zn(II) complexes of 1,3-diterpyridyl-substituted p-tert-butylcalix[4]arene

The calix[4]arene-based podand which incorporates two terpyridine functions in 1,3-alternate positions with flexible propylene spacers at lower rim has been prepared and subjected to complexation studies with some transition metal ions. Single-crystal structures of Mn(II), Co(II), and Zn(II) complexes were determined by X-ray diffraction. These metal complexes are formed with a 2 : 1 ratio of metal and ligand. Coordination of each metal is five-coordinate distorted trigonal-bipyramidal geometry by three nitrogen atoms from a terpyridyl unit and two chloride atoms.

Synthesis and crystal structures of Ag and Hg complexes of bis(N-heterocyclic carbenes) on p-tert-butylcalix[4]arene platform

A series of p-tert-butylcalix[4]arene 1,3-diimidazolium salts were successfully prepared by the alkylation of p-tert-butylcalix[4]arene with dibromoalkanes, and sequential substitution reaction with 1-alkylimidazole. Furthermore, coordination reactions of p-tert-butylcalix[4]arene 1,3-diimidazolium salts with silver oxide and mercury acetate gave novel Ag and Hg complexes of bis(N-heterocyclic carbenes) on p-tert-butylcalix[4]arene platform. The single-crystal structures of four p-tert-butylcalix[4]arene 1,3-diimidazolium salts and three metal complexes were successfully determined by X-ray diffraction. An Ag–Ag argentophilic interaction (Ag–Ag bond length is 3.1599(6) Å) is formed between the two Ag–NHC complexes and a dimetallic coordination mode exists in Hg–NHC complexes.

Correction to “Convenient Synthesis of Triphenylphosphanylidene Spiro[cyclopentane-1,3′-indolines] and Spiro[cyclopent[2]ene-1,3′-indolines] via Three-Component Reactions”

A misinterpretation of the CIF file for 2g shown in Figure 2 caused incorrect structures to be reported for compounds 2a−k. Abstract, captions for Table 2 and Scheme 2, and all mentions in the text. The compound name should be changed from spiro[cyclopent[2]ene-1,3′-indolines] to spiro[cyclopent[3]ene-1,3′-indolines]. Page 2656, column 1. The text should read, “At first, the addition of triphenylphosphine to hex-2-en-4-ynedioate gives intermediate E. Second, the addition of 1,3-dipolar zwitterionate (E) to isatinylidene malononitrile produces adduct F. Third, the intramolecular Michael addition of the carbanion to the 1,3-diene bearing a stronger electron-withdrawing triphenylphosphanyl cationin adduct F affords a cyclized intermediate (G), which in turn transfers to a phosphorus ylide intermediate (H) by allylic arrangement of carbanion. Finally, the phosphorus ylide transfers to the triphenylphosphanylidene spiro[cyclopent[3]ene-1,3′-indoline] 2.” The correct product for the reaction in Table 2 is shown: