title: Highly selective synthesis of pyrazole and spiropyrazoline phosphonates via base-assisted reaction of the Bestmann-Ohira reagent with enones.
abstract: Novel carbonylated pyrazole phosphonates have been synthesized as single regioisomers by treating conjugated enones, dienones, tropone, and quinone with the Bestmann-Ohira reagent under KOH/EtOH conditions at room temperature. Through an "interrupted" version of the above reaction, carbonylated spiropyrazoline phosphonates have been synthesized from arylidenecycloalkanones under similar conditions (K(2)CO(3)/EtOH) with absolute regio- and diastereoselectivity. The key structures were confirmed by detailed spectroscopic analysis and X-ray crystallography.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India.
authors.forename: Deepti
authors.initials: D
authors.lastname: Verma
authors.forename: Shaikh
authors.initials: S
authors.lastname: Mobin
authors.forename: Irishi N N
authors.initials: IN
authors.lastname: Namboothiri
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D063065:Organophosphonates / Q000138:chemical synthesis* / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D013379:Substrate Specificity
chemical_list: D000475:Alkenes; D007202:Indicators and Reagents; D007659:Ketones; D063065:Organophosphonates; D011720:Pyrazoles; C031280:pyrazole