Benzoxepine formation by the 1,7 electrocyclisation of diene-conjugated carbonyl ylides: studies on relative rates of cyclisation via intramolecular competition reactions
作者:Donal F. O’Shea、John T. Sharp
DOI:10.1039/a702962d
日期:——
groups and the thiophene ring are found to be ca. 10–20 times more reactive than phenyl. In cases where the 6-substituent is a substituted aryl group it has been found that, unlike the analogous nitrile ylides, aromatic substituents have little effect on the reactivity of the ring. The selectivity is unaffected by the nature of the substituent on the terminal atom of the carbonyl ylide. Mechanistic studies
Palladium-Catalyzed Cycloisomerization of 2-Ethynylbiaryls to 9-Methylidene Fluorenes
作者:Hongyu Guo、Sheng Zhang、Xiujuan Feng、Xiaoqiang Yu、Yoshinori Yamamoto、Ming Bao
DOI:10.1021/acs.orglett.2c00534
日期:2022.4.15
presence of weak acid at low temperature to afford 9-methylidene fluorenes in satisfactory to high yields. This new type of cycloisomerization of 2-ethynylbiaryls is operationally simple and scalable and exhibits high functional-group tolerance. Various synthetically useful functional groups, such as halogen atoms, as well as formyl, acetyl, methoxycarbonyl, cyano, and nitro groups, remain intact during