Xiaoxia Wang

Copper-catalyzed domino intramolecular cyclization: a facile and efficient approach to polycyclic indole derivatives

A mild and efficient Cu(2)O-catalyzed domino intramolecular C-N coupling/C-Y (Y = O, S, N) bond formation was successfully achieved. Thus oxazino[3,2-a]indole, thiazino[3,2-a]indole and indolo[2,1-b]quinazoline derivatives were facilely assembled from readily accessible gem-dibromovinyl systems. The protocol is general and practical, affording a variety of the indole-incorporated products in good to excellent yields even under air atmosphere.

An efficient and facile synthesis of benzimidazo[1,2-a]benzimidazoles via copper-catalyzed domino addition/double cyclization

A copper-catalyzed synthesis of benzimidazo[1,2-a]benzimidazoles by domino addition/double cyclization of bis-(o-haloaryl)carbodiimides with primary amines was developed. A variety of the desired polycyclic benzimidazoles were efficiently and facilely assembled. Multibonds and polycyclic moieties were directly constructed in one pot. 2-Bromo-2′-iodo-diarylcarbodiimides gave good selectivity.

Study on the coupling of acyclic esters with alkenes – the synthesis of 2-(2-hydroxyalkyl)cyclopropanols via cascade cyclization using allylsamarium bromide

The radical cyclization between aliphatic acyclic esters and alkenes was achieved unprecedentedly in the presence of allylsamarium bromide with HMPA and H(2)O as additives. The cascade radical cyclization-ring-opening-anionic cyclization allowed facile and efficient access to 2-(2-hydroxyalkyl)cyclopropanols from readily available materials.

Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

Summary A “stop-and-flow” strategy was developed for the chemoselective dioxygenation of alkenes with a PIFA-initiated cyclization. This method is conceived for the desymmetrization of seco-diene, and a series of substituted 5-hydroxymethyl-γ-lactones were constructed after hydrolysis. This strategy also differentiates terminally substituted alkenes and constitutes a potentially novel synthetic approach for the efficient synthesis toward velbanamine.

One-pot preparation of carbamoyl benzotriazoles and their applications in the preparation of ureas, hydrazinecarboxamides and carbamic esters

Carbamoyl benzotriazoles were conveniently synthesized in one-pot from carboxylic acids, diphenylphosphorazidate (DPPA) and benzotriazole (BtH). The reactivity and applications of carbamoyl benzotriazoles were also explored. Carbamoyl benzotriazoles react smoothly with amino acids, hydrazines and alcohols respectively, thus providing facile access to the corresponding ureas, hydrazinecarboxamides and carbamic esters in good to excellent yields.

Additive Tuned Selective Synthesis of Bicyclo[3.3.0]octan-1-ols and Bicyclo[3.1.0]hexan-1-ols Mediated by AllylSmBr

The selective construction of bicyclo[3.3.0]octan-1-ols and bicyclo[3.1.0]hexan-1-ols was achieved by using an allylSmBr/additive(s) system. By employing HMPA as the only additive, the momoallylation/ketone-alkene coupling occurred preferably and afforded bicyclo[3.3.0]octan-1-ols in good yields with high diastereoselectivities. While the ester-alkene coupling predominated to generate bicyclo[3.1.0]hexan-1-ols in moderate yields with excellent diastereoselectivities in the presence of a proton source, such as pyrrole as the coadditive with HMPA. The tunable reactivity of allylSmBr by additive(s) would make it a versatile reagent in organic synthesis.