title: DABCO catalyzed domino Michael/hydroalkoxylation reaction involving α-alkynyl-β-aryl nitroolefins: excellent stereoselective access to dihydropyrano[3,2-c]chromenes, pyranonaphthoquinones and related heterocycles.
abstract: Excellent stereoselective (up to ≤96 : 4 Z/E ratio) construction of pharmaceutically interesting functionalized pyrano[3,2-c]chromenes, pyranonaphthoquinones and related pyrano-fused heterocycles has been achieved in good to high yields (72-89%) through a domino Michael/hydroalkoxylation reaction involving several enolizable cyclic β-keto esters/1,3-dicarbonyls and α-arylacetylenyl-β-nitrostyrenes as binucleophiles in EtOH at room temperature using DABCO as an organocatalyst. Moreover, syn-2-benzyl-4-aryl-3,4-dihydropyrano[3,2-c]chromenes were obtained in high yields (81-86%) via a stereoselective denitrohydrogenation of the corresponding 2-benzylidene-3,4-dihydropyrano[3,2-c]chromenes using a catalytic amount of 10% Pd/C.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Indore, Simrol Campus, Indore, 452001, Madhya Pradesh, India. sampaks@iiti.ac.in.
authors.forename: Soumen
authors.initials: S
authors.lastname: Biswas
authors.affiliation: Department of Chemistry, Indian Institute of Technology Indore, Simrol Campus, Indore, 452001, Madhya Pradesh, India. sampaks@iiti.ac.in.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Dagar
authors.affiliation: Department of Chemistry, Indian Institute of Technology Indore, Simrol Campus, Indore, 452001, Madhya Pradesh, India. sampaks@iiti.ac.in.
authors.forename: Shaikh M
authors.initials: SM
authors.lastname: Mobin
authors.affiliation: Department of Chemistry, Indian Institute of Technology Indore, Simrol Campus, Indore, 452001, Madhya Pradesh, India. sampaks@iiti.ac.in.
authors.forename: Sampak
authors.initials: S
authors.lastname: Samanta
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis* / Q000737:chemistry; D009574:Nitro Compounds / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry*; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D001578:Benzopyrans; D006571:Heterocyclic Compounds; D009285:Naphthoquinones; D009574:Nitro Compounds; D010879:Piperazines; D011714:Pyrans; C007306:triethylenediamine