a simple, efficient, and high yielding one-pot protocol has been developed for the synthesis of 4h-benzo[b]pyrans scaffolds installing a three-component tandem knoevenagel-cyclocondensation reaction of an aldehyde, malononitrile and dimedone using guanidinium chloride as polyfunctional organocatalyst under solvent-free conditions in high to excellent yields. various aromatic aldehydes were util...

A novel catalytic synthesis of 3,3'-(arylmethylene)-bis-(4-hydroxy-2H-chromene-2-one) derivatives from a tandem condensation reaction of 4-hydroxycoumarin and aromatic aldehydes has been developed. The reaction occurs in water in the presence of Melamine trisulfonic acid as catalyst to give the corresponding products in good to high yields. This green approach has several advantages such as sho...

The concept of tandem catalysis, where sequential reactions catalyzed by different interfaces in single nanostructure give desirable product selectively, has previously been applied effectively in the production of propanal from methanol (via carbon monoxide and hydrogen) and ethylene via tandem hydroformylation. However, the underlying mechanism leading to enhanced product selectivity has rema...

Tandem reactions use consecutive reaction steps to efficiently synthesize compounds of high molecular complexity. This paper presents a tandem Pd-catalyzed Heck and alkoxycarbonylation reaction for the stereoselective synthesis of (E)-oxindolylidene acetates. The mechanism underlying the Pd-catalyzed tandem reaction involves the syn-carbopalladation of ynamides followed by alkoxycarbonylation w...

The enantioselective tandem Friedel-Crafts alkylation/Michael addition reaction of indoles with nitroolefin enoates catalyzed by a diphenylamine-linked bis(oxazoline)-Zn(OTf)2 complex was investigated. This tandem reaction afforded functionalized chiral chromans in good yields with moderate to high stereoselectivities (up to 95:5 dr, up to 99% ee).

We report the development of a tandem chemoenzymatic transformation that combines alkene metathesis with enzymatic epoxidation to provide aryl epoxides. The development of this one-pot reaction required substantial protein and reaction engineering to improve both selectivity and catalytic activity. Ultimately, this reaction converts a mixture of alkenes into a single epoxide product in high ena...

A copper-mediated tandem reaction of β-ketoesters/ketones with tertiary amines was achieved, which provides a simple and efficient approach to the synthesis of 2,3-dihydrofuran derivatives. In this tandem reaction, the tertiary amine not only offers the methylene moiety but also serves as the base.

A copper(ii) perchlorate-promoted tandem reaction of internal alkynol and salicyl N-tosylhydrazone provides a novel, concise method for constructing isochromeno[3,4-b]chromene in 35-94% yields. The tandem reaction involves cycloisomerization, formal [4+2] cycloaddition and an elimination process.

The first Ni-promoted prototype reaction based on the tandem C-H activation of heteroarenes with alkene isomerization is demonstrated, leading to the branched hydroheteroarylation products. Simultaneously, the reaction selectivity can be chemically switched to linear adducts through Ni-Al tandem catalysis.