Synthesis of [2.2]Paracyclophane-Fused Heterocycles via Palladium-Catalyzed C-H Activation/Annulation of [2.2]Paracyclophanecarboxamides with Arynes.

[2.2]Paracyclophane-fused heterocycles represent an important scaffold. Traditional approaches often suffer from tedious synthetic routes, and the development of catalytic synthesis of them remains in its infancy. Herein, by employing highly strained aryne intermediates as partners, we have developed a concise protocol by palladium-catalyzed C-H activation/annulation from [2.2]paracyclophanecarboxamide substrates. [2.2]Paracyclophane-fused quinolinone products are obtained in good yields (up to 84%). Furthermore, the utility of the process has been shown through the synthesis of [2.2]paracyclophane-fused heterocyclic catalysts.

SCpRh(III)-Catalyzed Enantioselective Synthesis of Atropisomers by C2-Arylation of Indoles with 1-Diazonaphthoquinones.

The Rh(III)-catalyzed highly enantioselective C2-arylation of indole derivatives with 1-diazonaphthoquinones is reported. In the presence of 2.5 mol % SCpRh complex and 20 mol % AgNO3, the C2-arylation reactions of indoles proceeded smoothly, affording a wide range of C2-arylated indole atropisomers in good yields and enantioselectivity (≤96% yield, ≤97% ee) under mild conditions. The method displays a broad substrate scope and good functional group tolerance.

CpxM(iii)-catalyzed enantioselective C-H functionalization through migratory insertion of metal-carbenes/nitrenes.

CpxM(iii)-catalyzed enantioselective C-H functionalization reactions have progressed rapidly using either chiral cyclopentadienyl ligands or appropriate chiral carboxylic acids. In this context, highly reactive carbene and nitrene precursors can serve as effective C-H coupling partners, providing a straightforward and efficient approach to access chiral molecules. In this review, we highlight the developments in CpxM(iii)-catalyzed enantioselective C-H functionalization reactions through migratory insertion of metal-carbenes/nitrenes by employing chiral CpxM(iii) complexes or achiral CpxM(iii) complexes combined with chiral carboxylic acids.

Oxygen-Linked Cyclopentadienyl Rhodium(III) Complexes-Catalyzed Asymmetric C-H Arylation of Benzo[h]quinolines with 1-Diazonaphthoquinones.

Chiral cyclopentadienyl rhodium (CpRh) complex-catalyzed asymmetric C-H functionalization reactions have witnessed a significant progress in organic synthesis. In sharp contrast, the reported chiral Cp ligands are limited to C-linked Cp and are often synthetically challenging. To address these issues, we have developed a novel class of tunable chiral cyclopentadienyl ligands bearing oxygen linkers, which were efficient catalysts for C-H arylation of benzo[h]quinolines with 1-diazonaphthoquinones, affording axially chiral heterobiaryls in excellent yields and enantioselectivity (up to 99 % yield, 98.5:1.5 er). Mechanistic studies suggest that the reaction is likely to proceed by electrophilic C-H activation, and followed by coupling of the cyclometalated rhodium(III) complex with 1-diazonaphthoquinones.

Unusual biaryl torsional strain promotes reactivity in Cu-catalyzed Sommelet-Hauser rearrangement.

A Cu-catalyzed Sommelet-Hauser dearomatization of dihydrophenanthridine and diazo compounds is reported for the synthesis of spiro-indolines. A spiro-structure with adjacent quaternary and tertiary carbon centers was constructed in one step as a single isomer. Increasing steric hindrance by introducing ortho-substituents dramatically improved substrate reactivity in this transformation.

Palladium-Catalyzed Enantioselective Synthesis of 2-Aryl Cyclohex-2-enone Atropisomers: Platform Molecules for the Divergent Synthesis of Axially Chiral Biaryl Compounds.

The palladium-catalyzed asymmetric synthesis of enone-based atropisomers from 2-iodo-3-methylcyclohex-2-enones and aryl boronic acid is reported. BoPhoz-type phosphine-aminophosphine ligands showed superior enantioselectivity over other ligands. These cyclohexenone-based atropisomers are useful compounds for further elaboration. The divergent synthesis of biaryl atropisomers with different ortho substituents was demonstrated.

Catalytically Asymmetric Pd/Norbornene Catalysis: Enantioselective Synthesis of (+)-Rhazinal, (+)-Rhazinilam, and (+)-Kopsiyunnanine C1-3.

A catalytically asymmetric palladium/norbornene-catalyzed reaction is reported, where α-aryl tetrahydroquinoline derived phosphoramidite L15 is found to be the optimum ligand. Taking advantage of this transformation, the concise and unified enantioselective syntheses of (+)-rhazinal, (+)-rhazinilam, and (+)-kopsiyunnanine C1, C2, and C3 are realized.

A Catalyst-Free Synthesis of Phosphinic Amides Using O-Benzoylhydroxylamines.

A practical approach for the synthesis of phosphinic amides via the coupling of secondary phosphine oxides (SPOs) with O-benzoylhydroxylamines has been reported. Simply heating the mixture of SPOs and O-benzoylhydroxylamines in the presence of K(2)CO(3) gave the phosphinic amides in moderate to excellent yields under an open air system. This method provides a practical and catalyst-free method for the synthesis of various synthetically valuable phosphinic amides.