Highly Enantioselective Copper-Catalyzed Alkylation of β-Ketoesters and Subsequent Cyclization to Spirolactones/Bi-spirolactones
作者:Qing-Hai Deng、Hubert Wadepohl、Lutz H. Gade
DOI:10.1021/ja211859w
日期:2012.2.15
Cu-catalyzed enantioselective alkylation of β-ketoesters using alcohols for in situ preparation of alkylating reagents is reported. A number of functionalized β-ketoesters containing a quaternary carbon stereocenter are obtained with up to 99% ee. The alkylation products derived from 2-substituted allylic alcohols or their corresponding iodides can then be converted to spirolactones, bi-spirolactones
报道了使用醇对 β-酮酯进行 Cu 催化的对映选择性烷基化,用于原位制备烷基化试剂。获得了许多含有季碳立体中心的官能化 β-酮酯,ee 高达 99%。然后可以将衍生自 2-取代烯丙醇或其相应碘化物的烷基化产物转化为螺内酯、双螺内酯和相关的手性目标产物。
Synthetic Studies toward Amphidinolide B<sub>1</sub>: Synthesis of the C<sub>9</sub>−C<sub>26</sub> Fragment
作者:Wei Zhang、Rich G. Carter
DOI:10.1021/ol051544e
日期:2005.9.1
[reaction: see text] The synthesis of the C9-C26 portion of amphidinolide B1 is described. A Fleming allylation followed by elimination was employed for the construction of the C13-C15 diene portion. Sharpless asymmetric dihydroxylation was utilized for regioselective functionalization of a styrene-derived alkene, in the presence of the C13-C15 diene functionality. A highly diastereoselective aldol
Cation Clock Reactions for the Determination of Relative Reaction Kinetics in Glycosylation Reactions: Applications to Gluco- and Mannopyranosyl Sulfoxide and Trichloroacetimidate Type Donors
作者:Philip O. Adero、Takayuki Furukawa、Min Huang、Debaraj Mukherjee、Pascal Retailleau、Luis Bohé、David Crich
DOI:10.1021/jacs.5b06126
日期:2015.8.19
method based on the intramolecular Sakurai reaction for probing the concentration dependence of the nucleophile in glycosylationreactions is described. The method is developed for the sulfoxide and trichloroacetimidate glycosylation protocols. The method reveals that O-glycosylation reactions have stronger concentration dependencies than C-glycosylation reactions consistent with a more associative, S(N)2-like
Reaction of Allylsilanes and Allylstannanes with Alkynes Catalyzed by Electrophilic Late Transition Metal Chlorides
作者:Carolina Fernández-Rivas、María Méndez、Cristina Nieto-Oberhuber、Antonio M. Echavarren
DOI:10.1021/jo025812n
日期:2002.7.1
The intramolecular reaction of allylsilanes and allylstannanes with alkynes proceeds catalytically in the presence of Pt(II), Pd(II), Ru(II), and Au(III) chlorides. Although more limited, AgOTf also catalyzes the cyclization. Usually, PtCl2 as the catalyst in methanol or acetone gives the best results. The reaction proceeds by exo attack of the allyl nucleophile on the alkyne to form five- or six-membered
Peroxycarbenium-Mediated C−C Bond Formation: Applications to the Synthesis of Hydroperoxides and Peroxides
作者:Patrick H. Dussault、In Quen Lee、Hyung-Jae Lee、Richard J. Lee、Q. Jason Niu、Jeffrey A. Schultz、Umesh R. Zope
DOI:10.1021/jo991714z
日期:2000.12.1
while SnCl(4) and trimethylsilyl triflate promote formation of peroxides. Lewis acid-promoted reactions of silylated hydroperoxyacetals furnish silylated hydroperoxides, which can be deprotected to homologated hydroperoxides. Hydroperoxyketals undergo Lewis acid-mediated allylation to furnish 1,2-dioxolanes via attack of hydroperoxide on the intermediate carbocation. Lewis acid-mediated cyclization