Metathesis Reaction of Diazo Compounds and para-Quinone Methides for C–C Double Bond Formation: Synthesis of Tetrasubstituted Alkenes and Quinolinones

Abstract

The para-quinone methides (p-QMs) are activated by Lewis acid and then attacked by diazo compounds. The following rearrangement leads to nitrogen gas extrusion and C-C double bond formation to constitute a metathesis reaction process. Therefore, the diazoester is transformed into tetrasubstituted alkenes, whereas the diazo-oxindole delivers the quinolinone products. Furthermore, the C-labeling experiments were also conducted to elucidate a possible mechanism.

A Review on Olefin Metathesis Reactions as a Green Method for the Synthesis of Organic Compounds

“…On the other hand, a metal alkylidene catalyst-free metathesis reaction for the construction of the C-C double bond is now taking view and interest in many organic laboratories. Haung et al (2016) synthesized tetrasubstituted quinolinones using diazo compounds and para-quinone methides via metathesis reactions using TiCl4 as the Lewis acid and dichloromethane as a solvent (Scheme 4) [16].…”

Catalyst-Free 1,6-Conjugate Addition/Aromatization/Sulfonylation of para-Quinone Methides: Facile Access to Diarylmethyl Sulfones

“…To address these limitations, developing efficient, green, and sustainable strategies to construct diarylmethyl sulfones remains important and is challenging. In continuation of our interest in constructing functionalized molecules, − herein, we report a catalyst-free, facile, and efficient route for the synthesis of diarylmethyl sulfones from the readily available starting materials, sulfonyl hydrazides , and p -quinone methides ( p -QMs), − which are widely used in modern organic synthesis because of the assembly of carbonyl and olefinic moieties (Figure b).…”

Synthesis of Quinone Methide Substituted Neonicotinoid Derivatives via 1,6-Conjugate Addition of N-Benzyl Nitro Ketene Aminals with para-Quinone Methides Accompanying Oxidation

“…NBNKAs belong to heterocyclic ketene aminals (HKAs) − which are widely used to construct molecular diverse heterocyclic compounds − such as spirooxindoles, , quinolones, pyridines, pyrroles, and others. However, the structural features of p -QMs result from the assembly of carbonyl and olefin moieties, and they have been widely used in a variety of addition reactions as universal Michael receptors, and are also chemically defined as neutral and zwitterionic resonance entities. , These structural features also allow for natural product synthesis as well as for the production of bioactive molecules. − There have been comprehensive reports produced about para -quinone methide reactions such as [3 + 2] addition, − [4 + 2] cycloaddition, [1 + 4] addition, and others. − Since Fan and Jørgensen reported on the 1,6-addition reaction of methylene quinone compounds, − many catalytic systems such as transition-metal catalysts (Figure ), − BF 3 ·Et 2 O (Figure ), , N -heterocyclic carbene catalysts (Figure ), , K 2 CO 3 (Figure ), , phosphoric acids (Figure ), , and other catalysts were reportedly used in the 1,6-addition reaction. ,…”

“…38−41 There have been comprehensive reports produced about para-quinone methide reactions such as [3 + 2] addition, 42−46 [4 + 2] cycloaddition, 47 [1 + 4] addition, 48 and others. 49−52 Since Fan and Jørgensen reported on the 1,6-addition reaction of methylene quinone compounds, 53−60 many catalytic systems such as transition-metal catalysts (Figure 2), 61−67 BF 3 •Et 2 O (Figure 2), 68,69 Nheterocyclic carbene catalysts (Figure 2), 70,71 K 2 CO 3 (Figure 2), 72,73 phosphoric acids (Figure 2), 74,75 and other catalysts were reportedly used in the 1,6-addition reaction. 76,77 Recently, the Li Xin group realized the organocatalyzed asymmetric 1,6conjugate addition of para-quinone methides with dicyanoolefins.…”