TWO TYPES OF INDIRECT CYCLODIMERIZATION OF BIACETYL VIA ITS ENOL SILYL ETHERS
نویسندگان
چکیده
منابع مشابه
Formal (3+3) cycloaddition of silyl enol ethers catalyzed by trifric imide: domino Michael addition-claisen condensation accompanied with isomerization of silyl enol ethers.
We describe here a Tf₂NH-catalyzed formal (3+3) cycloaddition of silyl enol ethers with acrylates as a new domino reaction. In the domino sequence, the catalyst activates Michael addition, deprotonation of the resulting silyloxonium cation and intramolecular Claisen condensation. It was found that reaction modes significantly depend on the reaction temperature. We also examined the mechanistic ...
متن کاملSpiroketals via oxidative rearrangement of enol ethers.
Oxidative rearrangement of cyclic enol ethers leads to alpha-alkoxyesters. In the presence of a neighboring spiroether, this approach provides a stereoselective access to spiroketals. A modified proposal for the biosynthesis of acutumine is presented.
متن کاملOne-pot synthesis of tropinone by tandem (domino) ene-type reactions of acetone silyl enol ethers.
A synthetic approach for tropane alkaloids on the basis of tandem (domino) ene-type reactions of acetone silyl enol ethers with iminium ions is shown to be triggered by intermolecular ene-type reactions followed by 6-(2,5) silatropic ene-type cyclizations.
متن کاملSynthesis of 2-substituted 7-hydroxybenzofuran-4-carboxylates via addition of silyl enol ethers to o-benzoquinone esters.
Mukaiyama Michael addition of silyl enol ethers 13 to the 1,2-quinone-4-carboxylate 6 (formed in situ by oxidation of the catechol ester 8) afforded the 2-subsituted 7-hydroxybenzofuran-4-carboxylates 14 in fair to good yields. Alkyl and aryl systems work well, but highly electron-rich silyl enol ethers could not be used because of competing oxidation.
متن کاملalpha-Nitration of Ketones via Enol Silyl Ethers. Radical Cations as Reactive Intermediates in Thermal and Photochemical Processes.
Highly colored (red) solutions of various enol silyl ethers and tetranitromethane (TNM) are readily bleached to afford good yields of alpha-nitro ketones in the dark at room temperature or below. Spectral analysis show the red colors to be associated with the intermolecular 1:1 electron donor-acceptor (EDA) complexes between the enol silyl ether and TNM. The formation of similar vividly colored...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Chemistry Letters
سال: 1977
ISSN: 0366-7022,1348-0715
DOI: 10.1246/cl.1977.1219