Zn(II) Chloride Promoted Benzannulation Strategy for One‐Pot Regioselective Synthesis of 6<i>H</i>‐Benzo[<i>c</i>]chromenes

Muralidhar, B.; Reddy, Sabbasani Rajasekhara

doi:10.1002/slct.201700311

Cited by 9 publications

(1 citation statement)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among acyclic substrates able to undergo a metal-promoted cyclization to give a polycyclic heterocycle, functionalized alkynes bearing a suitably placed heteronucleophile play a major role, as the triple bond can be easily electrophilically activated by a suitable metal species thus promoting the cyclization by intramolecular nucleophilic attack [ 1 , 2 , 3 , 4 , 5 ]. Usually, processes like these are promoted by costly metals (mainly gold [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], palladium [ 20 , 21 , 22 , 23 ], rhodium [ 24 , 25 , 26 ], platinum [ 27 , 28 , 29 ], and, occasionally, ruthenium [ 30 ]), while the use of less expensive metal species, such as cobalt [ 31 ], nickel [ 32 ], copper [ 33 , 34 , 35 , 36 ], zinc [ 37 , 38 , 39 , 40 ], and silver [ 41 , 42 ] compounds, has been scantly reported in the literature, and applied to a limited number of examples.…”

Section: Introductionmentioning

confidence: 99%

A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

et al. 2021

View full text Add to dashboard Cite

A straightforward approach to new polycyclic heterocycles, 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones, is presented. It is based on the ZnCl2-promoted deprotective 6-endo-dig heterocyclization of N-Boc-2-alkynylbenzimidazoles under mild conditions (CH2Cl2, 40 °C for 3 h). The zinc center plays a dual role, as it promotes Boc deprotection (with formation of the tert-butyl carbocation, which can be trapped by substrates bearing a nucleophilic group) and activates the triple bond toward intramolecular nucleophilic attack by the carbamate group. The structure of representative products has been confirmed by X-ray diffraction analysis.

show abstract

Section: Introductionmentioning

confidence: 99%

A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

et al. 2021

View full text Add to dashboard Cite

show abstract

Pd/C and TFA‐promoted One‐pot, Two‐step Cascade Reaction: An Effective Synthesis of Oxepines

et al. 2021

View full text Add to dashboard Cite

A Pd/C and TFA-promoted effective one-pot synthesis of oxepines starting from iodoheteroaryl/aryl ethers and terminal alkyne has been developed under mild conditions. This transformation involves intermolecular CÀ C bond formation between the aryl iodide and terminal alkynes followed by intramolecular hydroarylation of alkyne, affording the desired oxepines in good yields. A possible mechanism was proposed.

show abstract

Copper‐Mediated Relay Strategy Using Chlorination/Oxidation: An Effective Synthesis of Functionalized Coumarin Derivatives

et al. 2022

Self Cite

View full text Add to dashboard Cite

Chromene-fused heterocyclic compounds have shown fascinating biological and physiochemical properties and thus, the design and development of chromene-fused heterocyclic molecules is of significant interest in the field of synthetic organic chemistry. We report an innovative ligandand additive-free synthetic approach of 4-(phenylethynyl)-2Hchromene-3-carbaldehyde with phenylacetylenes has been described through sequential chlorination, benzannulation, benzylic sp 3 CÀ H bond functionalization, and ether oxidation for the formation of chloro-substituted-9-phenyl-6H-benzo[c]-chromen-6-ones with readily available chemicals under onepot, base-free conditions using CuCl 2 as sustainable catalyst. In this regioselective approach, we defined a reasonably longer cascade, which reveals the multiple role of chlorine as chlorine supplier, Lewis acid catalyst and oxidation rate promoter that tolerates a broad substrate scope and allows good product yields. The authenticated mechanism proceeds in a cascading fashion through the formation of multiple bonds.

show abstract

Zn(II) Chloride Promoted Benzannulation Strategy for One‐Pot Regioselective Synthesis of 6H‐Benzo[c]chromenes

Cited by 9 publications

References 52 publications

A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

Pd/C and TFA‐promoted One‐pot, Two‐step Cascade Reaction: An Effective Synthesis of Oxepines

Copper‐Mediated Relay Strategy Using Chlorination/Oxidation: An Effective Synthesis of Functionalized Coumarin Derivatives

Contact Info

Product

Resources

About