Pd(ii)–SDP-catalyzed enantioselective 5-exo-dig cyclization of γ-alkynoic acids: application to the synthesis of functionalized dihydofuran-2(3H)-ones containing a chiral quaternary carbon center
Cycloisomerization versus Hydration Reactions in Aqueous Media: A Au(III)-NHC Catalyst That Makes the Difference
作者:Eder Tomás-Mendivil、Patrick Y. Toullec、Josefina Díez、Salvador Conejero、Véronique Michelet、Victorio Cadierno
DOI:10.1021/ol300811e
日期:2012.5.18
A novel water-soluble Au(III)-NHC complex has been synthesized and successfully applied in the intramolecular cyclization of gamma-alkynoic acids into enol-lactones under biphasic toluene/water conditions, thus representing a rare example of an active and selective catalyst for this transformation In aqueous media. Remarkably, competing alkyne hydration processes were not observed, even during the desymmetrization reaction of challenging 1,6-diyne substrates. In addition, after phase separation, the water-soluble Au(III) catalyst could be recycled 10 times without loss of activity or selectivity.
Wichterle; Nemecek, Chemicke Listy, 1943, vol. 37, p. 105,108
作者:Wichterle、Nemecek
DOI:——
日期:——
Enantioselective, Desymmetrizing Bromolactonization of Alkynes
作者:Michael Wilking、Christian Mück-Lichtenfeld、Constantin G. Daniliuc、Ulrich Hennecke
DOI:10.1021/ja402910d
日期:2013.6.5
Asymmetric bromolactonizations of alkynes are possible using a desymmetrization approach. The commercially available catalyst (DHQD)(2)PHAL promotes these cyclizations in combination with cheap NBS as a bromine source to give bromoenol lactones in high yield and with high enantioselectivity. The bromoenol lactone products, containing a tetrasubstituted alkene and a quaternary stereocenter are valuable building blocks for synthetic chemistry.
ATKINSON R. S.; GRIMSHIRE M. J., J. CHEM. SOC. PERKIN TRANS.,(1986) N 7, 1215-1224
作者:ATKINSON R. S.、 GRIMSHIRE M. J.
DOI:——
日期:——
Atkinson, Robert S.; Grimshire, Michael J., Journal of the Chemical Society. Perkin transactions I, 1986, p. 1215 - 1224