Ytterbium triflate efficiently catalyzes an unusual cyclization of o-hydroxybenzaldehydes with 2,3-dihydrofuran and 3,4-dihydro-2H-pyran in the presence of trimethyl orthoformate at ambient temperature to afford a new class of compounds, furoand pyrano[2,3-b]benzopyrans in excellent yields with high diastereoselectivity. Also, o-hydroxybenzaldehydes reacted smoothly with acetophenones in the pr...

Hybrids of vinblastine and phomopsin, designed by a molecular modelling study, were elaborated in order to target tubulin. The key step of the synthesis (fragmentation and insertion of vindoline) was mediated by an internal N-carboxyanhydride (or O-acylcarbamate). This reaction was diastereospecific and addition of silver salts could reverse the diastereoselectivity. Even if the synthesized com...

A gold(I)-catalyzed enantioselective desymmetrization of 1,3-diols was achieved by intramolecular hydroalkoxylation of allenes. The catalyst system 3-F-dppe(AuCl)2/(R)-C8-TRIPAg proved to be specifically efficient to promote the desymmetrizing cyclization of 2-aryl-1,3-diols, which have proven challenging substrates in previous reports. Multisubstituted tetrahydrofurans were prepared in good yi...

We report a catalytic asymmetric reaction process that involves the use of solid-phase reagents and catalysts that constitute the packing of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of beta-lactams, to yield pure products with excellent enantio- and diastereoselectivity. We have identified several advantages to conducting chemical reactions ...

Platinum dichloride-catalyzed hydroxy- or alkoxycyclization of cyclohexadienynes gives indenol derivatives, whereas hydroxy- or alkoxycyclization of cycloheptadienynes produces azulenol derivatives. The cyclization reaction proceeds via a cyclopropyl platinacarbene intermediate and allows for the direct stereocontrol of three contiguous stereogenic centers of the fused bicyclic skeletons. The t...

Drug-like spirocyclic scaffolds have been prepared by fusing fully functionalized pyrrolidine with oxindoles in an approach based on 1,3-dipolar cycloaddition. Reaction between aziridine and 3-ylideneoxindole generated diverse spirooxindole-pyrrolidines in good yield (up to 95%) with high diastereoselectivity (up to >20:1). The reaction also proceeded smoothly with several other synthetically u...

Page Outlined in this paper is a series of work done towards the construction of bicyclo[2.2.2]diazaoctane structures found in a several natural products. Detailed work is shown for a general method of creating these cores by a domino sequence to rapidly generate these cores with enantio-and diastereoselectivity. A similar sequence this outlined and displayed in the formal synthesis of breviana...

A multicatalytic approach that combines a bifunctional Brønsted base-squaramide organocatalyst and Ag+ as Lewis acid has been applied in the reaction of unactivated ketones with tert-butyl isocyanoacetate to give chiral oxazolines bearing a quaternary stereocenter. The formal [3+2] cycloaddition provided high yields of the corresponding cis-oxazolines with good diastereoselectivity and excellen...