Ambident Reactivity of Medium-Ring Cycloalkane-1,3-dione Enolates1
摘要:
Cycloalkane-1,3-diones with ring sizes 7-10 have been converted to their enolates and subjected to a variety of ethylation and methylation reagent/solvent systems. The greatest amount of O-alkylation was encountered using ethyl tosylate in HMPA. The O/C alkylation ratios decreased with almost every reagent/solvent system as the ring size was increased. This trend is consistent with greater steric strain in the conjugated enolate resonance contributor, resulting in diminished O-attack as the ring size is increased.
Mechanism of intramolecular photocycloadditions of cyclooctenones
作者:Michael C. Pirrung、Nicholas J. G. Webster
DOI:10.1021/jo00392a020
日期:1987.8
PIRRUNG, MICHAEL C.;WEBSTER, NICHOLAS J. G., J. ORG. CHEM., 52,(1987) N 16, 3603-3613
作者:PIRRUNG, MICHAEL C.、WEBSTER, NICHOLAS J. G.
DOI:——
日期:——
Synthetic Applications in Radical/Radical Cationic Cascade Reactions
作者:Heiko Rinderhagen、Jochen Mattay
DOI:10.1002/chem.200304827
日期:2004.2.20
acetylenic side chain. The reactions result in bi- to tetracyclic ring systems via a fragmentation-radical/radical cationic addition reaction pathway with well defined ring juncture. The mode of cyclisation (endo/exo) can be partially controlled by addition of nucleophiles due to the suppression of radical cationic reaction pathways. Quantum chemical calculation of the cyclisation transition states underline
Ambident Reactivity of Medium-Ring Cycloalkane-1,3-dione Enolates<sup>1</sup>
作者:Glenn S. Thompson、Jerry A. Hirsch
DOI:10.1021/jo971515k
日期:1998.2.1
Cycloalkane-1,3-diones with ring sizes 7-10 have been converted to their enolates and subjected to a variety of ethylation and methylation reagent/solvent systems. The greatest amount of O-alkylation was encountered using ethyl tosylate in HMPA. The O/C alkylation ratios decreased with almost every reagent/solvent system as the ring size was increased. This trend is consistent with greater steric strain in the conjugated enolate resonance contributor, resulting in diminished O-attack as the ring size is increased.