Yuanhong Zhao

Palladium-catalyzed sequential arylation and allylic alkylation of highly functionalized ketones: a concise synthesis of mesembrine.

An unprecedented palladium-catalyzed sequential procedure toward arylation and allylic alkylation of highly functionalized cyclohexenones was developed. This new protocol leads to useful building blocks containing a benzylic quaternary carbon in only one step. A concise total synthesis of mesembrine based on this procedure was achieved in only five steps with 22% overall yield.

Imidazolylidene carbene ligated palladium catalysis of the Heck reaction in the presence of air

Five 1,3-disubstituted imidazolium salts were synthesized. Their Heck reaction activities were evaluated. A convenient, efficient and high yielding procedure based on these compounds for the arylation of olefins was developed. Heck reactions mediated by these palladium-N-heterocyclic carbene complexes were conducted under air and even in the presence of several common oxidants.

Efficient synthesis of β-amino-α,β-unsaturated carbonyl compounds

A versatile and high-yielding procedure for the synthesis of β-enamino esters and β-enaminones is presented: in the presence of tetraethyl orthosilicate, a number of highly functional β-enamino esters were obtained; this method provided an alternative for the formation of β-amino-α,β-unsaturated carbonyl compounds with mild and functional group compatible reaction conditions.

Silica Gel-Mediated Amide Bond Formation: An Environmentally Benign Method for Liquid-Phase Synthesis and Cytotoxic Activities of Amides

An efficient, functional group tolerable, and environmentally benign process for the synthesis of amides was developed. No activation reagents or scavengers are required in this process. Purification of desired compounds is easy, rapid, and cost-effective. This protocol provides an alternative for the combinatorial liquid-phase synthesis of amide libraries for drug discovery. By this method, a number of amides were prepared and evaluated in vitro against a panel of human tumor cell lines. Cinnamic amide IV-4 was found to be the most potent compound synthesized against four human tumor cell lines.

Efficient synthesis of esermethole and its analogues

In this work, a general and flexible synthetic route towards the synthesis of pyrroloindoline alkaloids was developed. This new strategy features with a palladium mediated sequential arylation-allylation of o-bromoanilides and leads to the construction of oxindoles bearing a full carbon quaternary center. The cheap triphenylphosphine was proved to be a highly effective ligand for this one pot transformation. On the basis of this new method, esermethole and its analogues were synthesized.

Suzuki cross-coupling mediated by tetradentate N-heterocyclic carbene (NHC)?palladium complexes in an environmentally benign solventElectronic supplementary information (ESI) available: general experimental procedures and characterization data. See http://www.rsc.org/suppdata/ob/b3/b302646a/

A highly effective, easy to handle and environmentally benign process for palladium mediated Suzuki cross-coupling was developed. By utilizing a solid support based NHC-palladium catalyst, cross couplings of aryl bromides with phenylboronic acid were achieved in neat water under air. A high ratio of substrate to catalyst was also realized.

Ullmann reaction in tetraethyl orthosilicate: a novel synthesis of triarylamines and diaryl ethers

A novel synthesis of triarylamines and diaryl ethers is reported; a feature of this process is the ligand-free copper-catalysed C-N and C-O bond formation in tetraethyl orthosilicate.