2,2-Di(ethoxy)vinyllithium: A synthetic equivalent of the ethyl acetate anion
作者:Heng-xu Wei、Manfred Schlosser
DOI:10.1016/0040-4039(96)00416-9
日期:1996.4
2,2-Diethoxyvinyllithium can be readily generated from 2-bromo-1,1-diethoxyethylene by treatment with butyllithium. When dissolved in tetrahydrofuran, it can be stored at −25 °C for hours, but decomposes rapidly at 0 °C.
2,2-Di(ethoxy)vinyllithium: Reactions with carbonyl compounds
作者:Abdelaziz Hiouni、Lucette Duhamel
DOI:10.1016/0040-4039(96)01163-x
日期:1996.7
2,2-Di(ethoxy)vinyllithium 2 generated from bromo ketene acetal 1 reacts with carbonyl compounds to give either β-hydroxy esters 5 or conjugated esters 6 or hydroxy ketene acetals 7 according to the work up.
2-Ethoxyvinyllithiums and diethoxyvinyllithiums : what makes them stable or fragile?
作者:Manfred Schlosser、Heng-xu Wei
DOI:10.1016/s0040-4020(96)01075-7
日期:1997.2
The elusive (E)-2-ethoxyvinyllithium can be readily generated in tetrahydrofuran at -75 degrees C from (E)-1-bromo-2-ethoxyethylene by halogen/metal exchange and subsequently trapped with electrophiles. Alkylation opens a convenient entry to (E)-configurated enethers. (E)-2-Ethoxyvinyllithium decomposes rapidly at -50 degrees C whereas its (Z)-isomer, which lacks the possibility to eliminate lithium ethoxide in a favorable anti-periplanar process, is stable under the same conditions. (E)-1,2-Diethoxyvinyllithium even sustains reflux temperatures (approximately 75 degrees C). 2,2-Diethoxyvinyllithium and (Z)-1,2-diethoxyvinyllithium can be conserved at 0 degrees C although this time loss of alcoholate can occur in the anti-mode. Obviously it matters whether the energy-rich ethoxyacetylene is formed as the elimination product or simple acetylene, as in the case of (E)-2-ethoxyvinyllithium. (C) 1997, Elsevier Science Ltd.
LEE, JU-YEON;HALL, (JR) H. K., J. ORG. CHEM., 55,(1990) N6, C. 4963-4964
作者:LEE, JU-YEON、HALL, (JR) H. K.
DOI:——
日期:——
Ketene Acetals. XIX. 2-Methylene-1,3-dioxolanes and 1,3-Dioxanes