Asymmetric Induction in Stereoselective Carbocyclization of Cyclohexanone Enamines
作者:Eugenius Butkus、Arvydas Stončius
DOI:10.1055/s-1999-2569
日期:1999.2
enantioselective synthesis of bicyclo[3.3.1]nonane diketones 3-5 was accomplished by (S)and (R)-2methoxymethylpyrrolidine induced asymmetric cyclization of cyclohexanoneenamines 1,2 in reaction with propenoyl chloride. A possible enantiodifferentiation reaction mechanism was suggested.
Stereoselective Baeyer–Villiger oxidation of some bridged bicyclic diketones
作者:Eugenius Butkus、Sigitas Stončius
DOI:10.1039/b103564a
日期:——
The regioselectivity of the Baeyer–Villigeroxidation of bicyclo[3.3.1]nonane and bicyclo[2.2.2]octane ketones 1–7 with carbonyl groups located at different positions and bearing other substituents in the bicyclic ring is studied. The impact of the formation of the tetrahedral intermediate and the ring-bond migratory aptitude are considered as major factors governing the reaction's regioselectivity
polycyclic polyprenylated acylphloroglucinols is developed using a ring-closing metathesis approach to give a substituted cyclooctene. This undergoes cyclization via an intramolecular acylation leading to a substituted bicyclo[3.3.1]nonan-9-one related to hyperforin, nemorosone, clusianone, garsubellin A and other members of the polyprenylated acylphloroglucinol.
使用闭环复分解方法开发了一种用于多环聚异戊二烯化酰基间苯三酚的模型化合物的方法,以提供取代的环辛烯。这通过分子内酰化进行环化,导致取代的双环 [3.3.1] nonan-9-one 与 hyperforin、nemorosone、clusianone、garsubellin A 和聚异戊二烯化酰基间苯三酚的其他成员相关。
Chiral bicyclic keto lactones: determination of the absolute configuration by the study of chiroptical properties and chemical correlation
作者:Sigitas Stončius、Ulf Berg、Eugenius Butkus
DOI:10.1016/j.tetasy.2004.06.018
日期:2004.8
rules for the determination of the absoluteconfiguration. Ab initio and molecular mechanics calculations revealed that for all compounds investigated a single conformer, that is c-tb for 1a–3a and 1–2b, and c-tc for 4a, tc-tc for 5a is prevalent in the gas phase at room temperature. The applicability and limitations of the semiempirical rules was demonstrated. The enantiospecific synthesis of enantiomerically