Catalytic I2-moist DMSO-mediated synthesis of valuable α-amidohydroxyketones and unsymmetrical gem-bisamides from benzimidates.

We developed an efficient and straightforward I2-catalyzed strategy for the synthesis of functionalized α-amidohydroxyketones and symmetrical and unsymmetrical bisamides using incipient benzimidate scaffolds as starting materials and moist-DMSO as a reagent and solvent. The developed method proceeds through chemoselective intermolecular N-C-bond formation of benzimidates and the α-C(sp3)-H bond of acetophenone moieties. The key advantages of these design approaches include broad substrate scope and moderate yields. High-resolution mass spectrometry of the reaction progress and labeling experiments provided suitable evidence regarding the possible mechanism. 1H nuclear magnetic resonance titration revealed notable interaction between the synthesized α-amidohydroxyketones and some anions as well as biologically important molecules, which revealed a promising recognition property of these valuable motifs.

ArCH(OMe)2--a Pt(IV)-catalyst originator for diverse annulation catalysis.

We discover an important property of a small molecule ArCH(OMe)2 which transforms catalytically inactive Pt(II)Br2 procatalyst in situ to an powerful catalyst Pt(IV)-species for diverse annulation reaction. The powerful catalytic system enables selective activation of C2-H/N-H and C2-H/C4-H of acetoacetanilide and C=O/C≡C of substituted butyne-1,2-dione for C-C/C-N, C-C/C-C and C-O/C-O bond-forming inter- and intramolecular annulation towards direct syntheses of functionalised 2-pyridones, cyclohexenones and 3(2H)-furanones respectively. In contrast to the common ligand, herein highly labile C-OMe bond of ArCH(OMe)2 is expected to react with PtBr2 towards generation of the high-valent active catalyst. Unlike catalyst promoter or initiator, the reaction does not occur with PtBr2 in the absence of ArCH(OMe)2. In situ generation of Pt(IV)-species and -OMe fragment of ArCH(OMe)2 were confirmed from the UV-vis characteristic peaks about 260 nm and trapping of -OMe group respectively. These observations provide new prospects and perspectives in catalysis for innovative catalyst design.

CeCl3·7H2O catalyzed C-C and C-N bond-forming cascade cyclization with subsequent side-chain functionalization and rearrangement: a domino approach to pentasubstituted pyrrole analogues.

CeCl(3)·7H(2)O is found as an efficient catalyst for new intermolecular domino reactions of three-, four- and seven-component assemblies of common precursors under benign reaction conditions. Generation of enaminioesters from ß-keto esters and primary amines, activation of their allylic sp(3) C-H, vinylic sp(2) C-H and N-H bonds, multi C-C and C-N bond-forming cascade cyclization with 1,2-diketones and subsequent side-chain alkylation have been developed to construct functionalized pentasubstituted pyrroles and their chiral analogues. The scope of the domino reaction is successfully explored toward synthesis of highly aryl-substituted pyrroles, pentasubstituted pyrroles bearing C2-olefinic side-chain and spiro-2-pyrrolinones and their chiral analogues via unusual side-chain amination, elimination and ring contraction. The new domino reaction is operationally simple, robust, substrate specific, selective and high yielding.

Efficient catalytic cyclizations of three and two imine assemblies: direct access to tetrahydroimidazo[1,5-c]imidazol-7-ones and imidazoles.

A cascade cyclization involving union of three imines by an organocatalyst proline is established to afford new fused-tetrahydroimidazo[1,5-c]imidazol-7-ones with excellent regio- and stereoselectivity. Another dehydrogenative cyclization by union of two imines is developed using the Cu(OTf)(2)-Ag(2)O combo catalyst to furnish functionalized imidazoles.

FeCl3⋠6H2O-catalyzed intermolecular-cascade cyclization of acetoacetanilide: aldehyde-tuned synthesis to valuable 2-pyridone analogues.

The first ever breakthrough toward activation of ß-ketoacetanilide and subsequent C-C and C-N bond-forming intermolecular-cascade cyclization processes is demonstrated by development of the unprecedented Lewis acid property of non-toxic FeCl(3)⋅6H(2)O. Aromatic, aliphatic, α,ß-unsaturated, chiral sugar-based and chromone aldehydes were regio- and stereoselectively cyclized with acetoacetanilides toward construction of valuable N-containing highly functionalized 2-pyridones (see scheme for an example).

Addition of halide to π-bond directly from aqueous NaX solution: a general strategy for installation of two different functional groups.

Activation of π-bond with organic Lewis acid and cationic surfactant mediated direct transfer of halides to alkyne and alkene are demonstrated to afford α,α-dihaloketones and other valuable synthons with outstanding selectivities.