title: Sequential one-pot combination of multireactions through multicatalysis: a general approach to rapid assembly of functionalized push-pull olefins, phenols, and 2-methyl-2H-chromenes.
abstract: A general, sustainable and practical process for the sequential cascade one-pot synthesis of library of highly substituted push-pull olefins, phenols and 2-methyl-2H-chromenes was reported through multicatalysis cascade (MCC) reactions. Direct sequential one-pot combination of amine- or amino acid-catalyzed cascade Knoevenagel/Michael/aldol condensation/decarboxylation with other reactions like amine- or amino acid-catalyzed cascade Claisen-Schmidt/iso-aromatization, Claisen-Schmidt/isomerization, Claisen-Schmidt/iso-aromatization/isomerization, Michael addition, Claisen-Schmidt/Michael, ruthenium-base-silica-catalyzed ring closing metathesis/base-induced ring-opening/benzylic oxidation/[1,7]-sigmatropic hydrogen shift, or ruthenium-base-heat-catalyzed ring closing metathesis/base-induced ring-opening/[1,7]-sigmatropic hydrogen shift reactions of alkyl acetoacetates, a variety of aldehydes and alkyl halides furnished the highly functionalized push-pull olefins, phenols and 2-methyl-2H-chromenes with high yields. The yields and regioselectivities were good to excellent. Evidence for a new reaction pathway involving in situ formation of novel push-pull dienamines under amine- or amino acid-catalysis is presented along with examples demonstrating the amenability of the process to MCC chemistry.
authors.affiliation: School of Chemistry, University of Hyderabad, Central University, Hyderabad 500 046, India. ramsc@uohyd.ernet.in
authors.forename: Dhevalapally B
authors.initials: DB
authors.lastname: Ramachary
authors.forename: Kinthada
authors.initials: K
authors.lastname: Ramakumar
authors.forename: Adluri
authors.initials: A
authors.lastname: Bharanishashank
authors.forename: Vidadala V
authors.initials: VV
authors.lastname: Narayana
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D054852:Small Molecule Libraries / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: C412074:5,7-dimethoxy-2-methyl-2H-benzopyran; D000475:Alkenes; D001578:Benzopyrans; D010636:Phenols; D054852:Small Molecule Libraries