anoate, a valuable chiral intermediate for the synthesis of lactacystin, was obtained in high yield and excellent anti-diastereoselectivity. The ketoreductase catalyzed reduction of α-cyanomethyl- and α-cyanoethyl-β-keto esters to form the corresponding opticallypure β-hydroxy esters, which are chiral intermediates for the synthesis of opticallypure α-substituted γ-butyro and δ-valerolactams, was
Termination of manganese(III)-based oxidative free-radical cyclizations by addition to nitriles. Formation of cyclopentanones and cyclohexanones
作者:Barry B. Snider、Brad O. Buckman
DOI:10.1021/jo00027a056
日期:1992.1
Mn(III)-based oxidative free-radical tandem cyclizations and annulations can be terminated by addition to nitriles. Cyclopentanones 20a (51%), 24a (57%), and 32a (54%) are formed in good yield. Annulation to give cyclohexanone 32b (41%) proceeds in moderate yield, although 20b (8%) and 24b (13%) are formed in poor yield in tandem cyclizations. Pyridine 39 (15%) is formed in ethanol by condensation of the enamine tautomer 37 of imine 31a with the oxidation byproduct 33a produced from radical 29a.
Synthesis of β-Functionalized α,β-Unsaturated Oximes via Silylation of Nitro Compounds
作者:Vitaly M. Danilenko、Alexander A. Tishkov、Sema L. Ioffe、Ilya M. Lyapkalo、Yury A. Strelenko、Vladimir A. Tartakovsky
DOI:10.1055/s-2002-23539
日期:——
A general method for the synthesis of conjugated enoximes 2 via silylation of functionalized aliphatic nitrocompounds 1 has been claborated. The configuration of obtained products has been determined by NMR spectroscopy.