Karlotoxin synthetic studies: concise synthesis of a C(42-63) B-ring tetrahydropyran fragment.

Starting from natural D-mannose, a C(42-63) B-ring tetrahydropyran fragment in karlotoxin 2 has been prepared via a common THP intermediate in a concise manner. E-selective Julia-Kocienski olefination efficiently assembled a C(51-63) chlorodiene subunit and a C(42-50) tetrahydropyran segment.

Mechanism study of copper-mediated one-pot reductive amination of aryl halides using trimethylsilyl azide.

Reaction mechanisms of the copper-mediated amination of aryl halides with trimethylsilyl azide (TMSN3) were analyzed on the basis of the time-course study using reaction monitoring FT-IR, trapping an intermediary aryl azide by the Huisgen reaction, and the analysis of the generated N2 gas during the reaction. This amination would proceed through multiple pathways via aryl radicals and copper(I) azide.

One-pot synthesis of 2-aminoquinoline-based alkaloids from acetonitrile.

α-Diaminoboryl carbanions, readily prepared from acetonitrile, stereoselectively convert 2-nitrobenzaldehydes into nitrophenyl (Z)-acrylonitriles. Subsequent reductive cyclization leads to a series of 2-aminoquinoline derivatives. The entire procedure is practically operated in a single flask.

An α-diaminoboryl carbanion assisted stereoselective single-pot preparation of α,ß-disubstituted acrylonitriles.

An α-diaminoboryl carbanion-mediated one-pot olefination directly converts an acetonitrile or the homologous nitrile into a series of α,ß-disubstituted acrylonitriles in a stereoselective manner. The protocol involves the formation of an α-substituted α-diaminoboryl acetonitrile and subsequent olefination with an aldehyde. The use of an aryl or conjugated aldehyde preferentially leads to a (Z)-acrylonitrile, while an aliphatic aldehyde gave an (E)-isomer as a major product. Two complementary approaches, a linear method and a divergent method, are developed.

Facile and convenient method of deuterium gas generation using a Pd/C-catalyzed H2-D2 exchange reaction and its application to synthesis of deuterium-labeled compounds.

The Pd/C-catalyzed H(2)-D(2) exchange reaction using a H(2)-D(2)O combination provided a general, efficient and environmentally friendly route for the preparation of deuterium gas (D(2)). H(2) sealed in a reaction flask was converted into nearly pure D(2), which could be used for the Pd/C-catalyzed one-pot reductive deuteration of various reducible functionalities and the chemoselective one-pot deuterogenation of olefin and acetylene. Additionally, we established the capturing method of the generated D(2) in a balloon, which was successfully applied to the Pd/C-catalyzed reductive mono-N-alkylation of a primary amine using nitrile as the alkylating reagent.