CuBr-mediated synthesis of 1,4-naphthoquinones via ring expansion of 2-aryl-1,3-indandiones

A CuBr-mediated direct insertion of alkenes into unstrained ring 2-aryl-1,3-indandiones is reported, which provides a one-carbon ring expansion strategy for the synthesis of 1,4-naphthoquinones. Entirely differing from the existing reports, the alkenes herein behave as C1 units to participate in annulation reactions. This transformation provides a facile route to access a class of highly functionalized 1,4-naphthoquinones with good yields, good functional-group tolerance and high atom-economy. Further research on the application of this reaction is currently underway in our laboratory.

t-BuOK mediated oxidative coupling amination of 1,4-naphthoquinone and related 3-indolylnaphthoquinones with amines

The transition-metal free amination of 1,4-naphthoquinone and related 3-indolylnaphthoquinones with amines, such as various (hetero)aromatic amine and aliphatic amine via t-BuOK-mediated oxidative coupling at room temperature has been developed. This reaction provides efficient access to the biologically important and synthetically useful 2-amino-1,4-naphthoquinones and 2-amino-3-indolylnaphthoquinones with good yields under mild conditions. The present protocol is simple, practical and shows good functional group tolerance. In addition, the obtained 2-amino-3-indolylnaphthoquinones were further transformed to synthesize polycyclic N-heterocycles.

Organocatalytic Asymmetric Domino Oxa-Michael-Mannich-[1,3]-Amino Rearrangement Reaction of N-Tosylsalicylimines to α,β-Unsaturated Aldehydes by Diarylprolinol Silyl Ethers

An organocatalytic asymmetric enantioselective domino oxa-Michael-Mannich-[1,3]-amino rearrangement reaction of N-tosylsalicylimines with a wide range of α,β-unsaturated aldehydes utilizing diarylprolinol silyl ether catalysis is described. The catalytic reactions proceed with excellent enantioselectivity (up to 99% ee) to produce the corresponding chair N-tosylimines-chromenes with a yield of up to 99%, tolerating a range of functional groups. This methodology offers a new method with great potential to further extend the synthetic power and versatility of chiral aminocatalysis.

New Developments of the Principle of Vinylogy as Applied to π-Extended Enolate-Type Donor Systems

The principle of vinylogy states that the electronic effects of a functional group in a molecule are possibly transmitted to a distal position through interposed conjugated multiple bonds. As an emblematic case, the nucleophilic character of a π-extended enolate-type chain system may be relayed from the legitimate α-site to the vinylogous γ, ε, ..., ω remote carbon sites along the chain, provided that suitable HOMO-raising strategies are adopted to transform the unsaturated pronucleophilic precursors into the reactive polyenolate species. On the other hand, when "unnatural" carbonyl ipso-sites are activated as nucleophiles (umpolung), vinylogation extends the nucleophilic character to "unnatural" β, δ, ... remote sites. Merging the principle of vinylogy with activation modalities and concepts such as iminium ion/enamine organocatalysis, NHC-organocatalysis, cooperative organo/metal catalysis, bifunctional organocatalysis, dicyanoalkylidene activation, and organocascade reactions represents an impressive step forward for all vinylogous transformations. This review article celebrates this evolutionary progress, by collecting, comparing, and critically describing the achievements made over the nine year period 2010-2018, in the generation of vinylogous enolate-type donor substrates and their use in chemical synthesis.

Highly enantioselective desymmetrization of prochiral cyclic α,α-dicyanoalkenes via the direct vinylogous Michael/cyclization domino reaction

A chiral N,N′-dioxide/Mg(ii) complex efficiently constructs spiroindolinones which include three adjacent atom chiralities and a tertiary carbon center at remote sites in up to 95% yield, with 99% ee and 20 : 1 dr.

Asymmetric [4 + 2] cycloadditions with 3-furfural derivatives and α-cyano-α,β-unsaturated ketones

An asymmetric [4 + 2] cycloaddition reaction with 2-benzyl-3-furfurals and α-cyano-chalcones was developed to afford chiral tetrahydrobenzofurans having dense substitutions.

Asymmetric cycloaddition reactions catalysed by diarylprolinol silyl ethers

Organocatalysis as a paint palette for asymmetric cycloaddition reactions.

Highly regio-, diastereo- and enantioselective deracemization of axially chiral 3-alkylideneoxindoles

A variety of (Z)-4-alkyl-2-((3-oxo-1,3-diarylpropyl)cyclohexylidene)-indolin-2-ones with three stereogenic centers at ξ-, γ- and δ′-positions were obtained in up to 95% yield, 98% ee and 99/1 dr in the presence of L-PiPh/Sc(iii).

Catalytic asymmetric reactions and synthesis of quinones

Organo- and metal–ligand catalysed asymmetric reactions of quinones lead to complex enantiopure compounds including quinones.