Synthesis of oxazole and furan derivatives via Rh2(OAc)4-catalyzed C≡X bond insertion of cyclic 2-diazo-1,3-diketones with nitriles and arylacetylenes

Fan, Chenli; He, Xinwei; Zuo, Yin; Shang, Yongjia

doi:10.1080/00397911.2018.1473441

Cited by 11 publications

(6 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Shang's Group reported an efficient approach for the synthesis of 2‐substituted‐6,7‐dihydrobenzo[ d ]oxazol‐4( 5H )‐ones ( 48 ) and 2‐aryl‐6,7‐dihydrobenzo‐furan‐4( 5H )‐ones ( 47 ) in very good yield via Rh(III)‐catalysed reaction of 2‐diazo‐1,3‐diketones ( 44 ) with nitriles ( 46 ) and aromatic alkynes ( 45 ) (Scheme 11). [22] A variety of reaction conditions were applied and found that reaction afforded highest yield with 1 mol% of Rh 2 (OAc) 2 ‐catalyst and 1 : 1 equivalents of both substrates at 60 °C for 4 h. A wide substrate scope was explored and presence of electron‐donating groups or electron‐withdrawing groups on the benzene ring at the 2‐ or 4‐position provided satisfactory results. However, the presence of aliphatic terminal alkynes, like hept‐1‐yne, gave no desired product, thus demonstrating that conjugation on the aromatic ring promoted to this reaction.…”

Section: Rh(ii)‐catalyzed Reactionmentioning

confidence: 99%

“…Novikov et al reported a tandem process for the synthesis of 5H-pyrazino [2,3-b] indoles (22) derivatives by using 2Hazirines (20) and 3-diazoindolin-2-imines (21) in the presence of Rh 2 (OAc) 4 as a catalyst (Scheme 7). [18] Additionally, another tandem strategy to form 5H-pyrazino [2,3-b] indole 3-carboxylates was reported in which reaction started with 5-alkoxyisoxazoles which readily converted into 2H-azirines 2-carboxylate in-situ.…”

Section: Synthesis Of N-containing Heterocyclesmentioning

confidence: 99%

“…Shang's Group reported an efficient approach for the synthesis of 2-substituted-6,7-dihydrobenzo[d]oxazol-4(5H)ones (48) and 2-aryl-6,7-dihydrobenzo-furan-4(5H)-ones (47) in very good yield via Rh(III)-catalysed reaction of 2-diazo-1,3diketones (44) with nitriles (46) and aromatic alkynes (45) (Scheme 11). [22] A variety of reaction conditions were applied Scheme 10. Rhodium-catalysed reaction of 4-diazoisochroman-3-imines as a carbene precursors and found that reaction afforded highest yield with 1 mol% of Rh 2 (OAc) 2 -catalyst and 1 : 1 equivalents of both substrates at 60 °C for 4 h. A wide substrate scope was explored and presence of electron-donating groups or electron-withdrawing groups on the benzene ring at the 2-or 4-position provided satisfactory results.…”

Section: Synthesis Of N-and O-containing Heterocyclesmentioning

confidence: 99%

See 2 more Smart Citations

Rhodium‐Catalyzed Cascade Reactions using Diazo Compounds as a Carbene Precursor to Construct Diverse Heterocycles

2021

View full text Add to dashboard Cite

Diazo compounds being used as a precursor of carbenes in synthetic chemistry by reacting them in different manners like photochemically, thermally or with metal catalysts. Further, the use of metals as a catalyst generates metallocarbenes in the reaction medium which has similar reactivity like free carbenes. In this context, a number of transition metal catalysts like Rh, Pd, Cu, Ru, Ir, Fe etc. have been employed to generate metal bound carbenes in the reaction medium. Among various metal catalyst, rhodium being used extensively in industry as well as in academia to catalyze a number of cascade transformations containing carbene insertion/transfer. In this review, we are covering the efforts made in the last five years toward the synthesis of highly important heterocyclic compounds such as isoquinoline, indoles, isocoumines, oxazoles, carbazoles etc. through rhodium catalysed cascade reactions containing carbene transfer as the vital step.

show abstract

Section: Rh(ii)‐catalyzed Reactionmentioning

confidence: 99%

Section: Synthesis Of N-containing Heterocyclesmentioning

confidence: 99%

Section: Synthesis Of N-and O-containing Heterocyclesmentioning

confidence: 99%

See 1 more Smart Citation

Rhodium‐Catalyzed Cascade Reactions using Diazo Compounds as a Carbene Precursor to Construct Diverse Heterocycles

2021

View full text Add to dashboard Cite

show abstract

“…Alicyclic diazocarbonyl compounds have also been employed in oxazole synthesis. Thus, in 2018, Fan and co-workers described the synthesis of 6,7-dihydrobenzo[ d ]oxazol-4(5 H )-ones 23 by reacting cyclic diazo diketones 21 with nitriles 22 [ 29 ]. The best yields were obtained with non-substituted diazo substrates.…”

Section: Azoles With Two Heteroatomsmentioning

confidence: 99%

Diazocarbonyl and Related Compounds in the Synthesis of Azoles

et al. 2021

View full text Add to dashboard Cite

Diazocarbonyl compounds have found numerous applications in many areas of chemistry. Among the most developed fields of diazo chemistry is the preparation of azoles from diazo compounds. This approach represents a useful alternative to more conventional methods of the synthesis of azoles. A comprehensive review on the preparation of various azoles (oxazoles, thiazoles, imidazoles, pyrazoles, triazoles, and tetrazoles) from diazocarbonyl and related compounds is presented for the first time along with discussion of advantages and disadvantages of «diazo» approaches to azoles.

show abstract

“…Therefore, the broad bioactivities and chemical reactivity have stimulated chemists to develop several approaches for constructing dihydrobenzofuran‐4‐one (DBF) and SOE derivatives. [ 25–28 ] However, these synthetic approaches do not explain why the yield percent of DBF dominates over its constitutional isomer SOE. More materially, whether the reaction is thermodynamic or kinetically controlled, DFT calculation predicting the electronic structure, reactivity, and spectroscopic feature of DBF and SOE has not been carried out.…”

Section: Introductionmentioning

confidence: 99%

Rh(II)‐mediated one‐pot synthesis of dihydrobenzofuran and spiro[2.5]oct‐1‐ene: Experimental and DFT studies

Hoque

Bari

Khan

2021

J of Physical Organic Chem

View full text Add to dashboard Cite

This study represents an experimental and computational approach to investigate the rhodium‐catalyzed one‐pot synthesis of dihydrobenzofuran‐4‐one (DBF) and spiro[2.5]oct‐1‐ene (SOE) derivatives. Density functional theory (DFT) calculations were performed at B3LYP and M06‐2X level theory. For mechanistic studies, the calculation employing B3LYP/GenECP/LanL2DZ/6‐311++G(d,p) level of theory demonstrated that a [3 + 2] cycloaddition reaction between diazo compound and phenylacetylene (PhA) proceeds through a two‐step mechanism via a barrierless and highly exergonic process with relative free energy 73.61 kcal/mol to yield the kinetically favored DBF derivatives (50%–62.5%). In contrast, the assemble of SOE derivatives follows [2 + 1] cycloaddition between in situ generated cyclohexane‐1,3‐dione carbene‐2 and PhA, with the potential energy barrier 4.41 kJ/mol. Thermochemistry calculation disclosed that the cycloaddition reactions are spontaneous, and DBF (6a) is thermodynamically more stable than its constitutional isomer SOE (7a) by 42.59 kcal/mol. However, natural bond orbital (NBO), HOMO–LUMO energy gaps (4.62–4.89 eV), dipole moments, polarizability, first‐order hyperpolarizability, and global reactivity descriptors were calculated to understand products' structural features. Additionally, Merck Molecular Force Field (MMFF94), followed by the B3LYP level of theory, was applied to predict the relative stability for the various conformations of 6b and 7b. The Boltzmann weighted average 1H chemical shift computed by GIAO‐B3LYP/6‐311+(2d,p) method and UV‐Vis absorption calculated using time‐dependent density functional theory (TD‐DFT) agree with experimental results. Finally, the synthesis of DBF and SOE derivatives is herein illustrated.

show abstract

Synthesis of oxazole and furan derivatives via Rh₂(OAc)₄-catalyzed C≡X bond insertion of cyclic 2-diazo-1,3-diketones with nitriles and arylacetylenes

Cited by 11 publications

References 21 publications

Rhodium‐Catalyzed Cascade Reactions using Diazo Compounds as a Carbene Precursor to Construct Diverse Heterocycles

Rhodium‐Catalyzed Cascade Reactions using Diazo Compounds as a Carbene Precursor to Construct Diverse Heterocycles

Diazocarbonyl and Related Compounds in the Synthesis of Azoles

Rh(II)‐mediated one‐pot synthesis of dihydrobenzofuran and spiro[2.5]oct‐1‐ene: Experimental and DFT studies

Contact Info

Product

Resources

About