Organocatalytic Enantioselective γ-Elimination: Applications in the Preparation of Chiral Peroxides and Epoxides

CuI-Catalyzed Dearomatization/Peroxidation/Cyclization Cascade of Pyrrole-Tethered Indoles

A mild CuI-catalyzed dearomatization/peroxidation/cyclization cascade of pyrrole-tethered indoles has been reached, providing peroxide-incorporated indolizino[8,7-b]indole derivatives in acceptable to good yields (46-76%). Dehydrogenated peroxide can be obtained by the use of a FeCl3/TBHP (tBuOOH)/2,2,2-trifluoroethanol (TFE) system at 50 °C.

Visible Light-Mediated Co(II) Catalyzed Synthesis of α,β-Epoxy Ketones by Oxidative Coupling of Alkenes and Aldehydes in Water

A one-step, two-component visible light-mediated CoCl2·6H2O-catalyzed oxidative acylation of alkenes by aldehydes to synthesize α,β-epoxy ketone has been achieved in water at room temperature. The photocatalytic activity of Co(II) presented a remarkable achievement for synthesis of α,β-epoxy ketones from aldehydes and olefins, with a wide substrate compatibility including aromatic, heteroaromatic and aliphatic aldehydes, styrenes with both electron-donating and withdrawing groups, α-substituted styrenes, stilbene, acrylates, and even the challenging unactivated aliphatic alkenes. Mechanistic studies including radical trapping experiments, intermediate detection by GCMS, Hammett analysis, and DFT studies unveil the nature of the photocatalytic pathway.

TBHP/Et3N-Promoted Chemoselective Formylation and Peroxidation of Pyrrolo[2,1-a]isoquinolines

An efficient formylation of pyrrolo[2,1-a]isoquinoline derivatives has been reached by the use of TBHP (tBuOOH) and Et3N as the mediator. In this strategy, CHO and CDO can be readily incorporated into heteroarenes by the utilization of CHCl3 and CDCl3 as the carbonyl sources. Interestingly, a solvent-controlled chemoselectivity was observed. The use of PhCl as a solvent resulted in dearomatization and peroxidation of pyrrolo[2,1-a]isoquinolines, delivering functionalized peroxides in 53-64% yields.

Iron-Catalyzed Synthesis of Peroxylpyrrolo[2,1-a]isoquinolines through Oxidative Dearomatization

A mild late-stage modification of pyrrolo[2,1-a]isoquinolines was established through iron-catalyzed oxidative dearomatization and peroxidation. Peroxylated pyrroloisoquinolines have been prepared readily with hydroperoxide in low to good yields (up to 72%) at room temperature. Interestingly, the treatment of fully aromatized pyrrolo[1,2-a]quinolines under the current reaction system resulted in the formation of ring-opening products.

CuII-Catalyzed cis-Selective Synthesis of Ketoepoxides from Phenacyl Bromides and Water

A verity of α,β-ketoepoxides was synthesized using a Cu^II-catalyzed oxidative C-C/O-C coupled cyclization strategy with high yield and cis-selectivity. Water is used as the source of oxygen and phenacyl bromide as the carbon in the valuable epoxides. The self-coupling method was extended to cross-coupling between phenacyl bromides with benzyl bromides. A high cis-diastereoselectivity was observed in all the synthesized ketoepoxides. Control experiments and density functional theory (DFT) study were performed to understand the Cu^II-Cu^I transition mechanism.

Enantioselective Peroxidation of C-Alkynyl Imines Enabled by Chiral BINOL Calcium Phosphate

Herein, we reported a catalytic enantioselective addition of C-alkynyl imines with hydroperoxides catalyzd by chiral BINOL calcium phosphate, affording a broad range of enantioenriched α-peroxy propargylamines in good yields (80-99%)...

Selective oxidation of alcohol-d 1 to aldehyde-d 1 using MnO2

The selective oxidation of alcohol-d₁ to prepare aldehyde-d₁ was newly developed by means of NaBD₄ reduction/activated MnO₂ oxidation. Various aldehyde-d₁ derivatives including aromatic and unsaturated aldehyde-d₁ can be prepared with a high deuterium incorporation ratio (up to 98% D). Halogens (chloride, bromide, and iodide), alkene, alkyne, ester, nitro, and cyano groups in the substrates are tolerated under the mild conditions.

A facile method for deutrium incorporation into aldehydes by mild reduction of NaBD₄ of aldehydes and MnO₂ oxidation (98% D) is disclosed.