109-50-2Relevant articles and documents
(Z)-3-alkylidene-4,5-dihydro-4-hydroxy-5-methyl-2-(3H)-furanones by regio- and diastereoselective ene reaction of singlet oxygen (Schenk reaction) with γ-hydroxy vinylstannanes: An enantioselective synthesis of dihydromahubanolide B
Adam,Klug
, p. 567 - 572 (1994)
(Z)-3-Alkylidene-4,5-dihydro-4-hydroxy-5-methyl-2-(3H)-furanones 5 were prepared from appropriately substituted propargylic alcohols 1 by a sequence of hydromagnesation to γ-hydroxy vinylstannanes 2, subsequent photooxygenation and reduction to stannyl diols 3, iododestannylation to iodo diols 4, and finally cyclization by palladium-catalyzed carbonylation (for 5a) or Ni(CO)2(PPh3)2 (for 5b,c). The reaction sequence can be performed enantioselectively by starting with chiral propargylic alcohols. The current approach constitutes a convenient four-step synthesis of optically active lactones 5 from readily available starting materials and is applied herein to the preparation of the natural lactone dihydromahubanolide B.
Phosphine-Catalyzed Intermolecular Annulations of Fluorinated ortho-Aminophenones with Alkynones – The Switchable [4+2] or [4+2]/[3+2] Cycloaddition
Zhang, Yanshun,Sun, Yaoliang,Wei, Yin,Shi, Min
supporting information, p. 2129 - 2135 (2019/03/13)
A phosphine-catalyzed intermolecular annulation reaction of functionalized ortho-aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2-alkynylquinolines and benzo-fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. (Figure presented.).
In situ generation of nucleophilic allenes by the gold-catalyzed rearrangement of propargylic esters for the highly diastereoselective formation of intermolecular C(sp3)-C(sp2) bonds
Yu, Yang,Yang, Weibo,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 7586 - 7589 (2013/07/26)
New perspectives, in particular for the synthesis of isochromane derivatives (see scheme), are provided by the title reaction. Excellent diastereoselectivites are achieved in this reaction which proceeds through a gold-catalyzed 1,3-acyloxy migration. In some cases exclusively the Z isomer is detected. Copyright
Synthesis of novel 2H,5H-dihydrofuran-3-yl ketones via ISNC reactions
Grandbois, Matthew L.,Betsch, Kelsie J.,Buchanan, William D.,Duffy-Matzner, Jetty L.
supporting information; scheme or table, p. 6446 - 6449 (2011/02/23)
Unique 1-[2H,5H-dihydrofur-3-yl]ketones have been synthesized from propargylic nitroethers via intramolecular cycloadditions involving silyl nitronates. Various substituent groups were placed on the 2 and 5 positions of the dihydrofuran rings. We examined the scope of the long-range coupling in proton NMR of the oxo-dihydrofuran products. The identities of the diastereomers resulting from the Michael addition/cycloaddition reactions were tentatively assigned for the first time. CAChe MNDO PM5 and CONFLEX programs were engaged to assist with the identification of these stereoisomers. The reaction times and conditions for these oxo-dihydrofurans were found to be different than that of the published dihydrofuranals, which led us to propose a different mechanism.
