A palladium polyaniline complex: a simple and efficient catalyst for batch and flow Suzuki-Miyaura cross-couplings.

A novel palladium polyaniline complex (Pd@PANI) was synthesized via a one-pot method using a low concentration of hydrogen peroxide (3 wt%) as a mild oxidant. Pd@PANI was employed to catalyze Suzuki-Miyaura cross-couplings with 0.11 ppm levels of palladium and high turnover numbers (up to 6.1 × 104). Various aromatic halides and aromatic boric acids were used as reaction partners to prepare the biaryl compounds in high yields. Application of the method in the synthesis of D-fructose derivatives was also performed. Furthermore, the catalyst was evaluated under a flow process to provide the corresponding products in good yields with shorter residence times and lower temperatures in more convenient operations compared with the batch conditions.

Total Synthesis of Pagoamide A.

The first total synthesis of the thiazole-containing cyclic depsipeptide pagoamide A, is detailed. The longest linear sequence of the liquid-phase synthesis comprises 9 long linear steps from simple known starting materials, which led to the unambiguous structural confirmation of pagoamide A.

Total Synthesis and Structural Reassignment of Laingolide A.

The asymmetric total synthesis of four diastereomers of laingolide A was achieved, which led to the unambiguous assignment of the stereochemistry of the natural product. The salient features of the convergent, fully stereocontrolled approach were a copper-catalysed stereospecific Kumada-type coupling, a Julia-Kocienski olefination and an RCM/alkene migration sequence to access the desired macrocyclic enamide.

Studies toward the Synthesis of Iriomoteolide-2a: Construction of the C(6)-C(28) Fragment.

The synthesis of an appropriately functionalized advanced C(6-28) fragment (3) of the marine macrolide iriomoteolide-2a (1) has been achieved in a highly efficient manner. The C(6)-C(18) fragment of 1 is prepared via a radical cyclization of a vinyl ether intermediate and palladium-promoted hydrostannylation/iodination. Paterson aldol reaction and Peterson olefination are used to construct the C(19)-C(28) fragment. The union of the C(6)-C(18) and C(19)-C(28) fragments is accomplished via a Suzuki-Miyaura coupling reaction.

Catalyst- and solvent-free approach to 2-arylated quinolines via [5 + 1] annulation of 2-methylquinolines with diynones.

A novel route for the synthesis of 2-arylated quinolines through a [5 + 1] annulation directly from 2-methylquinolines and diynones under catalyst-free and solvent-free conditions was disclosed. This synthetic process was atom-economic, with good tolerance of a broad range of functional groups, and with great practical worth.

Catalyst-Free Synthesis of Pyrrolo[1,2-a]quinolines via Dehydration/[3 + 2] Cycloaddition Directly from 2-Methylquinolines, Aldehydes, and Alkynoates.

A simple and efficient catalyst-free synthesis of pyrrolo[1,2-a]quinoline derivatives from 2-methylquinolines, aldehydes, and alkynoates via dehydration/[3 + 2] cycloaddition has been developed. The reaction conditions are tolerant to air, and H2O is the only byproduct of this transformation, thus offering an environmentally benign process with a wide range of potential applications in organic synthesis and medicinal chemistry.