Bis(1-cyanovinyl acetate) Is a Linear Precursor to 3-Oxidopyrylium Ions
作者:Sidney Malik Wilkerson-Hill、Shota Sawano、Richmond Sarpong
DOI:10.1021/acs.joc.6b02111
日期:2016.11.18
Herein we describe the first approach to 3-oxidopyrylium ions from a linear precursor. Heating bis(1-cyanovinyl acetate) in the presence of a trace amount of pyridinium p-toluenesulfonate results in a series of acyl group transfers and an intramolecular cyclization event to form a 3-oxidopyrylium ion that can be trapped by reaction with several dipolarophiles. When treated with dienes, the result is
Gold-Catalyzed Cyclopenta- and Cycloheptannulation Cascades: A Stereocontrolled Approach to the Scaffold of Frondosins A and B
作者:David Garayalde、Karolin Krüger、Cristina Nevado
DOI:10.1002/anie.201006105
日期:2011.1.24
Golden cascades: Two diastereoselective gold‐catalyzed cascade processes in which propargyl acetates react with alkenes or 1,4‐dienes afford highly substituted five‐ and seven‐membered rings, respectively (see scheme). The concerted nature of the gold‐catalyzed Cope rearrangement has been used in the formal enantioselective synthesis of marine norsesquiterpenoids Frondosins A and B.
The Diels–Alder reactivity of 2-vinylindenes: synthesis of functionalized tetrahydrofluorenes
作者:Sidney M. Wilkerson-Hill、Christián M. Lavados、Richmond Sarpong
DOI:10.1016/j.tet.2016.03.074
日期:2016.6
electron-demand Diels–Alder cycloaddition reaction between 2-vinylindenes and various dienophiles. Electron rich 2-vinylindenes bearing methoxy groups at the 4- and 7- positions were accessed through their corresponding 2-indenylpivalates obtained using a Pt-catalyzed cycloisomerization reaction. DFT calculations were used to rationalize the observed regioselectivity in the Diels–Alder reaction, and