Enantioselective 1,3-Dipolar Cycloadditions of Diazoacetates with Electron-Deficient Olefins
作者:Mukund P. Sibi、Levi M. Stanley、Takahiro Soeta
DOI:10.1021/ol070364x
日期:2007.4.1
[reaction: see text] A general strategy for highly enantioselective 1,3-dipolarcycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyrazolines
Decarbonylative Radical Coupling of α-Aminoacyl Tellurides: Single-Step Preparation of γ-Amino and α,β-Diamino Acids and Rapid Synthesis of Gabapentin and Manzacidin A
coupling method has been developed for the single‐step generation of various γ‐amino acids and α,β‐diamino acids from α‐aminoacyl tellurides. Upon activation by Et3B and O2 at ambient temperature, α‐aminoacyl tellurides were readily converted into α‐amino carbon radicals through facile decarbonylation, which then reacted intermolecularly with acrylates or glyoxylic oxime ethers. This mild and powerful
Enantioselective 1,3-Dipolar Cycloaddition Reaction between Diazoacetates and α-Substituted Acroleins: Total Synthesis of Manzacidin A
作者:Taichi Kano、Takuya Hashimoto、Keiji Maruoka
DOI:10.1021/ja056851u
日期:2006.2.1
A titanium BINOLate catalyzed asymmetric1,3-dipolarcycloaddition reaction between alpha-substituted acroleins and alkyl diazoacetates has been developed. With this methodology in hand, chiral 2-pyrazolines containing a quaternary stereogenic center were obtained in high to excellent enantioselectivities (up to 95% ee). The synthetic utility of the optically enriched 2-pyrazoline thus obtained was
An efficient synthetic method for stereoselective construction of asymmetric quaternary carbon stereocenters, bearingnitrogen in the form of Boc-protected allyl amines, has been developed. This methodology is employed in the synthesis of marine alkaloids, manzacidin A and C.
Short and stereoselective synthesis of manzacidins A and C, and their enantiomers
作者:Kentaro Oe、Tetsuro Shinada、Yasufumi Ohfune
DOI:10.1016/j.tetlet.2008.10.074
日期:2008.12
A short and stereoselective synthesis of manzacidins A and C, and their enantiomers was achieved via stereoselective hydrogenation reactions of dehydroamino acid esters 5-8 using a chiral Rh catalyst. (C) 2008 Elsevier Ltd. Ail rights reserved.