title: Formal (4+1) Cycloaddition and Enantioselective Michael-Henry Cascade Reactions To Synthesize Spiro[4,5]decanes and Spirooxindole Polycycles.
abstract: Spiro[4,5]decanes and polycyclic compounds bearing spiro[4,5]decane systems are important biofunctional molecules. Described are diastereoselective formal (4+1) cycloaddition reactions to afford oxindole-functionalized spiro[4,5]decanes and organocatalytic enantioselective Michael-Henry cascade reactions of the (4+1) cycloaddition products to generate spirooxindole polycyclic derivatives bearing the spiro[4,5]decane system. Spiro[4,5]decanes bearing oxindoles containing three stereogenic centers and spirooxindole polycycles having seven stereogenic centers, including two all-carbon chiral quaternary centers and one tetrasubstituted chiral carbon center, were obtained with high diastereo- and enantioselectivities.
authors.affiliation: Chemistry and Chemical Bioengineering Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan.
authors.forename: Ji-Rong
authors.identifier: 0000-0002-9272-3390
authors.initials: JR
authors.lastname: Huang
authors.affiliation: Chemistry and Chemical Bioengineering Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan.
authors.forename: Muhammad
authors.identifier: 0000-0002-8329-3464
authors.initials: M
authors.lastname: Sohail
authors.affiliation: Frontier Research Center for Advanced Material and Life Science, Faculty of Advanced Life Science, Hokkaido University, Kita 21 Nishi 11, Sapporo, 001-0021, Japan.
authors.forename: Tohru
authors.identifier: 0000-0002-4965-7383
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Frontier Research Center for Advanced Material and Life Science, Faculty of Advanced Life Science, Hokkaido University, Kita 21 Nishi 11, Sapporo, 001-0021, Japan.
authors.forename: Kenji
authors.identifier: 0000-0002-1424-1054
authors.initials: K
authors.lastname: Monde
authors.affiliation: Chemistry and Chemical Bioengineering Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan.
authors.forename: Fujie
authors.identifier: 0000-0001-6388-9343
authors.initials: F
authors.lastname: Tanaka
keywords: Michael addition; asymmetric catalysis; cycloaddition; organocatalysis; spiro compounds