中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | methyl 2,5-dioxopentanoate | 80994-17-8 | C6H8O4 | 144.127 |
A cyclopropanone, a cyclopropenone, cyclobutanones, a cyclobutane-1,3-dione, and a cyclobutene-1,2-dione reacted with dimethoxycarbene to afford acetals of the next larger ring by formal insertion of the carbene into a CC bond α to the carbonyl group. When either of two saturated α-ring carbons could be involved in the process, the ring expansion was selective, affording primarily the product of apparent insertion into the more substituted ring bond. With 2,3-dimethoxycyclobutene-1,2-dione, insertion occurred between the carbonyl groups and with β-propiolactone it occurred at the lactone bond. β-Propiolactam, however, reacted by insertion of the carbene into the NH bond.Key words: β-propiolactone, cyclobutanone, cyclobutananedione, cyclopropanone, dialkoxycarbene.