title: Organocatalytic Enantioselective Synthesis of Tetrahydrofluoren-9-ones via Vinylogous Michael Addition/Henry Reaction Cascade of 1,3-Indandione-Derived Pronucleophiles.
abstract: An unprecedented organocatalytic enantioselective vinylogous Michael addition/Henry cyclization cascade is presented for the synthesis of highly substituted tetrahydrofluoren-9-ones 3 employing novel 1,3-indandione-derived pronucleophiles 1a-g and nitroalkenes 2. Following a very simple protocol, a wide range of products were obtained in good to excellent yields and with excellent enantioinduction (43-98% yield, up to 98% ee). The reaction proceeded with excellent diastereocontrol despite the simultaneous generation of four stereogenic centers. Surprisingly, when 2-(1-phenylethylidene)-1H-indandione (1h) was used as a pronucleophile, no cyclization was observed, and only Michael addition adducts 4a-x were furnished in very good yields and excellent enantioselectivities.
authors: Department of Chemistry, National Taiwan Normal University , 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
authors: Lennart
authors: L
authors: Möhlmann
authors: Department of Chemistry, National Taiwan Normal University , 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
authors: Geng-Hua
authors: GH
authors: Chang
authors: Department of Chemistry, National Taiwan Normal University , 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
authors: G
authors: G
authors: Madhusudhan Reddy
authors: Department of Chemistry, National Taiwan Normal University , 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
authors: Chia-Jui
authors: CJ
authors: Lee
authors: Department of Chemistry, National Taiwan Normal University , 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
authors: Wenwei
authors: W
authors: Lin