Cycloadditions of Oxacyclic Allenes and a Catalytic Asymmetric Entryway to Enantioenriched Cyclic Allenes. Issue 17 (20th March 2019)

• Record Type: Journal Article
• Authors: Yamano, Michael M.; Knapp, Rachel R.; Ngamnithiporn, Aurapat; Ramirez, Melissa; Houk, Kendall N.; Stoltz, Brian M.; Garg, Neil K.
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 17(2019)
• Page Start: 5653
• Page End: 5657
• Publication Date: 2019-03-20
• Subjects: asymmetric catalysis -- catalysis -- cyclic allenes -- cycloadditions -- heterocycles; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201900503
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The chemistry of strained cyclic alkynes has undergone a renaissance over the past two decades. However, a related species, strained cyclic allenes, especially heterocyclic derivatives, have only recently resurfaced and represent another class of valuable intermediates. We report a mild and facile means to generate the parent 3, 4‐oxacyclic allene from a readily accessible silyl triflate precursor, and then trap it in (4+2), (3+2), and (2+2) reactions to provide a variety of cycloadducts. In addition, we describe a catalytic, decarboxylative asymmetric allylic alkylation performed on an α‐silylated substrate, to ultimately permit access to an enantioenriched allene. Generation and trapping of the enantioenriched cyclic allene occurs with complete transfer of stereochemical information in a Diels–Alder cycloaddition through a point‐chirality, axial‐chirality, point‐chirality transfer process. Abstract : Caught in a trap : A mild and facile method is reported to generate 3, 4‐oxacyclohexadienes. Trapping through (4+2), (3+2), and (2+2) reactions provides a variety of cycloadducts. In addition, a catalytic asymmetric approach for synthesizing enantioenriched cyclic allene precursors is described.