Chemoselective Switch in the Asymmetric Organocatalysis of 5H-Oxazol-4-ones andN-Itaconimides: Addition-Protonation or [4+2] Cycloaddition

Organocatalytic Stereoconvergent Synthesis of α-CF3 Amides: Triketopiperazines and Their Heterocyclic Metamorphosis

The highly enantioselective alkylation of α-CF₃ enolates, generated from triketopiperazines, has been accomplished through use of a bifunctional thiourea organocatalyst to facilitate 1,4-addition to varied enone acceptors. On treatment with appropriate nitrogen nucleophiles, the chiral triketopiperazine products undergo a metamorphosis, to provide novel fused heterocyclic lactams such as extended pyrazolopyrimidines.

Highly chemo-, enantio-, and diastereoselective [4 + 2] cycloaddition of 5H-thiazol-4-ones with N-itaconimides

A dipeptide-based urea-amide tertiary amine (DP-UAA) was shown to be an effective Brønsted base catalyst for the first asymmetric annulation reaction between 5H-thiazol-4-ones and N-itaconimides. High levels of enantioselectivity (up to 99% ee) and diastereoselectivity (>19:1 dr) were obtained for a series of spirocyclic 1,4-sulfur-bridged piperidinone-based succinimides.

Asymmetric tandem conjugate addition–protonation to forge chiral secondary C–O bonds for quaternary carbon stereocenters at the nonadjacent β-position

The first asymmetric tandem conjugate addition–protonation to methylene 1,3-oxazolidine-2,4-diones has been developed, thus providing a direct and efficient approach to assemble chiral secondary C–O bonds for quaternary carbon stereocenters and thiols at the nonadjacent β-position.

An enantioselective conjugate addition reaction of 3-substituted benzothiophen-2-ones and 2-phthalimidoacrylates

A highly enantioselective conjugate addition reaction of 3-substituted benzothiophen-2-ones to 2-phthalimidoacrylates has been developed using a bifunctional tertiary-amine thiourea catalyst.

Catalyst-controlled switch of regioselectivity in the asymmetric allylic alkylation of oxazolones with MBHCs

A catalyst-controlled switch of regioselectivity in asymmetric allylic alkylation of oxazolones with MBHCs was described.

Organocatalytic asymmetric conjugate addition of diaryloxazolidin-2,4-diones to nitroolefins: an efficient approach to chiral α-aryl-α-hydroxy carboxylic acids

The first asymmetric conjugate addition of diaryloxazolidin-2,4-diones to nitroolefins using an l-threonine-based tertiary amine-urea catalyst has been developed.

Organocatalytic asymmetric formal arylation of benzofuran-2(3H)-ones with cooperative visible light photocatalysis

An asymmetric arylation of benzofuran-2(3H)-ones with 1-naphthols has been developed through a cooperative visible light photocatalysis with asymmetric hydrogen-bond catalysis.

Reaction control in heterogeneous catalysis using montmorillonite: switching between acid-catalysed and red-ox processes

For a montmorillonite clay modified with a super-acid (CF₃SO₃H), two different modes of behaviour can take place simply by a judicious choice of reaction conditions.