an-Xin Ji

Copper-catalyzed direct oxidative synthesis of α-ketoamides from aryl methyl ketones, amines, and molecular oxygen

A novel and efficient copper-catalyzed direct oxidative synthesis of α-ketoamides from aryl methyl ketones, amines, and molecular oxygen has been developed under mild and neat conditions. 18O labeling experiments revealed that both oxygen atoms of the α-ketoamides derived from molecular oxygen.

Gold-Catalyzed Three-Component Tandem Process: An Efficient and Facile Assembly of Complex Butenolides from Alkynes, Amines, and Glyoxylic Acid

An efficient and facile gold-catalyzed three-component tandem process for the assembly of two types of highly functionalized butenolides has been developed. In this reaction system, more than four chemical bonds are formed by a single gold catalyst. The present tandem protocol includes a direct coupling of alkynes, amines, and glyoxylic acid and subsequent exclusively endo-selective cycloisomerization of alkynoic acids along with intermolecular electrophilic trapping; it utilizes three simple and commercially available starting materials to assemble architecturally complex and appealing butenolide scaffolds bearing other reactive sites for further manipulation.

Copper-catalyzed direct oxyphosphorylation of alkynes with H-phosphine oxides and dioxygen: A convenient approach to β-ketophosphine oxides

ABSTRACT A simple and facile copper-catalyzed synthesis of β-ketophosphine oxides via direct oxyphosphorylation of alkynes with H-phosphine oxides and dioxygen has been developed under mild conditions without any base or cocatalyst. A radical reaction pathway for the formation of β-ketophosphine oxides is proposed. An 18O labeling experiment suggested that the carbonyl oxygen atom of β-ketophosphine oxides originated from dioxygen. GRAPHICAL ABSTRACT

Copper-catalyzed aerobic oxidative coupling of ketones with P(O)–H compounds leading to β-ketophosphine oxides

A facile and efficient copper-catalyzed one-pot method for the construction of β-ketophosphine oxides has been developed via aerobic oxidative coupling of various ketones with P(O)–H compounds assisted by TBSOTf (t-butyldimethylsilyl triflate). Through this methodology, a series of β-ketophosphine oxides can be easily obtained in moderate to good yields with favorable functional group tolerance under very mild conditions. Isotope-labeling experiments suggested that the carbonyl oxygen atom of β-ketophosphine oxides originated from dioxygen.

Synthesis and evaluation of structurally constrained imidazolidin derivatives as potent dipeptidyl peptidase IV inhibitors.

To find potent and selective inhibitors of dipeptidyl peptidase IV (DPP-IV), we synthesized a series of 2-cyanopyrrolidine derivatives with constrained imidazolidin ring and tested their activities against DPP-IV. Most of them exhibited submicromolar inhibitory activities against DPP-IV. The most potent compound among these is (S)-1-(2-(2-(3-(3,4-dimethoxyphenyl)-2-oxoimidazolidin-1-yl)ethyl-amino)acetyl)pyrrolidine-2-carbonitrile (6n), which is a 2 nM DPP-IV inhibitor.

Efficient Synthesis of α,β-Diamino Acid Derivatives by In(III)-Catalyzed Regioselective Addition of Amines to Aziridines

Abstract An efficient catalytic method for the synthesis of α, β-diamino acid derivatives has been developed via regioselective ring opening of aziridines by amines in the presence of indium(III) salt under very mild reaction conditions. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Synthesis and Evaluation of Novel Compounds as Potent Dipeptidyl Peptidase IV Inhibitors

A series of new 2-cyanopyrrolidine derivatives with constrained imidazolidin ring were synthesized, Their structures were confirmed by 1H NMR spectroscopy and/or mass spectrometry, and their activities were evaluated in vitro. They were proven to possess submicromolar inhibitory activities against dipeptidyl peptidase IV.

Transition-metal-free PhI(OAc)2-promoted highly selective hydroboration of terminal alkynes under air

A new transition-metal-free PhI(OAc)2-promoted hydroboration reaction of terminal alkynes with bis(pinacolato)diboron has been developed at room temperature under air. A series of vinyl boronates could be conveniently and efficiently obtained in moderate to good yields with good regioselectivity and stereoselectivity as well as favorable functional group tolerance. The key I–B intermediates were first demonstrated in the present reaction system that explains the proposed mechanism.

INDIUM-PROMOTED ALLYLATION OF ALKYNES WITH ALLYLIC ALCOHOLS: HIGHLY REGIOSELECTIVE SYNTHESIS OF HALOGEN-SUBSTITUTED 1,4-DIENES

Abstract Indium-promoted allylation of alkynes by direct use of allyl alcohols as the allylating agents has been developed under mild conditions, in which a wide range of allylic alcohols and alkynes (both aromatic and aliphatic alkynes) could be tolerated, and the corresponding halogen-substituted 1,4-dienes were obtained in moderate to excellent yields. GRAPHICAL ABSTRACT