title: Organocatalytic, Asymmetric Synthesis of Aza-Quaternary Center of Izidine Alkaloids: Synthesis of (-)-Tricyclic Skeleton of Cylindricine.
abstract: We report a highly efficient, enantioselective, organocatalytic method for the synthesis of izidinone alkaloids containing a bridgehead aza-quaternary center using ketone-derived N,O-hemiaminal with a tethered acetal. Alkyl-, aryl-, and alkenyl-substituted substrates cyclize to the respective products with excellent enantioselectivities. Five- and seven-membered ring formation has also been established. Furthermore, synthesis of the tricyclic skeleton of cylindricine alkaloids has been achieved in high yield.
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute , Lucknow 226031, India.
authors.forename: Kyatham
authors.initials: K
authors.lastname: Srinivas
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute , Lucknow 226031, India.
authors.forename: Nishant
authors.initials: N
authors.lastname: Singh
authors.affiliation: School of Physical Science, Jawaharlal Nehru University , New Delhi 110067, India.
authors.forename: Dinabandhu
authors.initials: D
authors.lastname: Das
authors.affiliation: Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute , Lucknow 226031, India.
authors.forename: Dipankar
authors.identifier: 0000-0002-4861-7232
authors.initials: D
authors.lastname: Koley