title: Highly enantioselective [4+2] annulation via organocatalytic Mannich-reductive cyclization: one-pot synthesis of functionalized piperidines.
abstract: A new method for one-pot synthesis of 2,3-substituted piperidine from N-PMP aldimine and aqueous glutaraldehyde via formal [4+2] cycloaddition is reported. This reaction involves organocatalytic direct Mannich reaction-reductive cyclization with high yields (up to 90%) and excellent enantioselectivities (up to >99%). The practicability of this method is also shown at a gram scale as well as through the synthesis of functionalized (-)-anabasine.
authors.affiliation: Department of Chemistry, Birla Institute of Technology and Science, Pilani 333 031, Rajasthan, India. indresh.chemistry@gmail.com
authors.forename: Indresh
authors.initials: I
authors.lastname: Kumar
authors.forename: Panduga
authors.initials: P
authors.lastname: Ramaraju
authors.forename: Nisar A
authors.initials: NA
authors.lastname: Mir
authors.forename: Deepika
authors.initials: D
authors.lastname: Singh
authors.forename: Vivek K
authors.initials: VK
authors.lastname: Gupta
authors.lastname: Rajnikant
mesh_terms: D002384:Catalysis; D003500:Cyclization; D061565:Cycloaddition Reaction; D005976:Glutaral / Q000737:chemistry; D007097:Imines / Q000737:chemistry; D010880:Piperidines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D007097:Imines; D010880:Piperidines; D005976:Glutaral