title: Formation of diethyl 2-amino-1-cyclopentenylphosphonates: a simple synthesis with a unique mechanism.
abstract: Reaction of diethyl 5-chloro-1-pentynylphosphonate with primary and secondary amines produces novel 2-amino-1-cyclopentenylphosphonates, 1, in excellent isolated yields (79-88%). Calculations supported by experimental facts point to a two-step mechanism: an initial amine addition to give a zwitterionic intermediate followed by cyclization and proton transfer. Calculations rule out the formation of an enamine as an intermediate.
authors.affiliation: Department of Medicinal Chemistry and Natural Products, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Abed Al Aziz
authors.initials: AA
authors.lastname: Al Quntar
authors.forename: Hemant Kumar
authors.initials: HK
authors.lastname: Srivastava
authors.forename: Morris
authors.initials: M
authors.lastname: Srebnik
authors.forename: Artem
authors.initials: A
authors.lastname: Melman
authors.forename: Rachel
authors.initials: R
authors.lastname: Ta-Shma
authors.forename: Avital
authors.initials: A
authors.lastname: Shurki
mesh_terms: D000588:Amines / Q000737:chemistry*; D003517:Cyclopentanes / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D063065:Organophosphonates / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000588:Amines; D003517:Cyclopentanes; D005030:Ethylenes; D063065:Organophosphonates; C036216:ethylene