An Efficient Procedure for the Preparation of (<i>E</i>)-α-Alkylidenecycloalkanones Mediated by a CeCl<sub>3</sub>·7H<sub>2</sub>O−NaI System. Novel Methodology for the Synthesis of (<i>S</i>)-(−)-Pulegone<sup>1</sup>
synthons used as the key intermediates in many important syntheses. Because of their potential, a general method of preparation from readily available starting materials, under very mild conditions, was considered to be worthwhile. Cerium(III) chlorideheptahydrate in combination with sodiumiodide in refluxing acetonitrile promotes a regio- and stereoselective beta-elimination reaction to (E)-2-alky
Catalytic Asymmetric Construction of Spirocycles Containing Pyrrolidine Motifs and Spiro Quaternary Stereogenic Centers via 1,3-Dipolar Cycloaddition of Azomethine Ylides with 2-Alkylidene-Cycloketones
作者:Tang-Lin Liu、Zhao-Lin He、Qing-Hua Li、Hai-Yan Tao、Chun-Jiang Wang
DOI:10.1002/adsc.201100104
日期:2011.7
The first catalyticasymmetric 1,3‐dipolar cycloaddition of azomethineylides with various sterically hindered α,α,β‐trisubstituted 2‐alkylidene‐cycloketones has been developed successfully with silver acetate/TF‐BiphamPhos complex for the construction of spiro heterocyclic compounds containingpyrrolidine motifs and a spiro quaternary stereogenic carbon center. The highly efficient catalytic system exhibited
Catalytic Asymmetric Spirocyclizing Diels–Alder Reactions of Enones: Stereoselective Total and Formal Syntheses of α-Chamigrene, β-Chamigrene, Laurencenone C, Colletoic Acid, and Omphalic Acid
作者:Santanu Ghosh、Johannes Eike Erchinger、Rajat Maji、Benjamin List
DOI:10.1021/jacs.2c01971
日期:2022.4.20
We disclose a general catalytic enantioselective Diels–Alderreaction of exo-enones with dienes to give spirocyclanes. The obtained products feature highly congested quaternary stereogenic spirocenters and are used in concise total and formal syntheses of several sesquiterpenes, including of α-chamigrene, β-chamigrene, laurencenone C, colletoic acid, and omphalic acid. The stereo- and regioselectivities
Copper-Catalysed Asymmetric 1,4-Addition of Organozinc Compounds to Linear Aliphatic Enones Using 2,2′-Dihydroxy 3,3′-Dithioether Derivatives of 1,1′-Binaphthalene
作者:Christoph Börner、Michael R. Dennis、Ekkehard Sinn、Simon Woodward