205673-79-6Relevant articles and documents
Stereodivergent Synthesis of Enantioenriched γ-Butyrolactones Bearing Two Vicinal Stereocenters Enabled by Synergistic Copper and Iridium Catalysis
Wang, Chun-Jiang,Wei, Liang,Xiao, Lu
supporting information, p. 24930 - 24940 (2021/10/23)
By virtue of a fundamentally new reaction model of azomethine ylide serving as a two-atom synthon, we present the first example of stereodivergent preparation of γ-butyrolactones via synergistic Cu/Ir-catalyzed asymmetric cascade allylation/lactonization, and all four stereoisomers of γ-butyrolactones bearing two vicinal stereocenters are accessible with excellent diastereoselective and enantioselective control. The chiral IrIII-π-allyl intermediate was separated and characterized to understand the origin of the regio- and stereoselectivity of the initial C?C bond formation process. Control experiments shed some light on the catalyst/substrate and catalyst/catalyst interactions in this dual catalytic system to rationalize the related kinetic/dynamic kinetic resolution process with different catalyst combinations. The enantioenriched γ-butyrolactone products were converted into an array of structurally complex chiral molecules and organocatalysts that were otherwise inaccessible.
Asymmetric Hydroformylation of 4-Vinyl-1,3-dioxolan-2-one
Pongrácz, Péter,Kollár, László
, p. 1430 - 1436 (2017/03/27)
A chiral cyclic carbonate, 4-vinyl-1,3-dioxolan-2-one was used as racemic substrate in asymmetric hydroformylation. The catalysts were formed in situ from “pre-formed” PtCl2(diphosphine) and tin(II) chloride. (2S,4S)-2,4-Bis(diphenylphosphinopentane ((S,S)-BDPP)), (S,S)-2,3-O-izopropylidine-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane ((S,S)-DIOP)), and (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl ((R)-BINAP)) were used as optically active diphosphine ligands. The platinum-containing catalytic systems provided surprisingly high activity. The hydroformylation selectivities of up to 97% were accompanied by perfect regioselectivity towards the dioxolane-based linear aldehyde. The enantiomeric composition of all components in the reaction mixture was determined and followed throughout the reaction. The unreacted 4-vinyl-1,3-dioxolan-2-one was recovered in optically active form. The kinetic resolution was rationalized using the enantiomeric composition of the substrate and the products.
