开发了一种有效的四步方案,用于功能化茚满的构建。通过与溴酸酯(2-溴丙酸乙酯,溴乙酸乙酯或2-溴丁酸乙酯)的Reformatsky反应,将1-Tetralones转化为不饱和酯,然后将所形成的β-羟基酯脱水。酯部分的还原导致带有内环双键的均烯丙基醇。这些3-烯醇的氧化重排是通过三硝酸th(TTN)在AcOH / H 2 O的2:1混合物中进行的,导致环收缩产物的产率适中至非常好。研究了该序列的十四个例子。还研究了用TTN氧化由2-四氢萘酮制备的3-链烯醇。对于这些底物,未观察到环收缩反应。
开发了一种有效的四步方案,用于功能化茚满的构建。通过与溴酸酯(2-溴丙酸乙酯,溴乙酸乙酯或2-溴丁酸乙酯)的Reformatsky反应,将1-Tetralones转化为不饱和酯,然后将所形成的β-羟基酯脱水。酯部分的还原导致带有内环双键的均烯丙基醇。这些3-烯醇的氧化重排是通过三硝酸th(TTN)在AcOH / H 2 O的2:1混合物中进行的,导致环收缩产物的产率适中至非常好。研究了该序列的十四个例子。还研究了用TTN氧化由2-四氢萘酮制备的3-链烯醇。对于这些底物,未观察到环收缩反应。
Traditional database query languages such as datalog and SQL allow the user to specify only mandatory requirements on the data to be retrieved from a database. In many applications, it may he natural to express not only mandatory requirements but also preferences on the data to be retrieved. Lacroix and Lavency(10)) extended SQL with a notion of preference and showed how the resulting query language could still be translated into the domain relational calculus. We explore the use of I,reference in databases in the setting of datalog. We introduce the formalism of preference datalog programs (PDPs) as preference logic programs without uninterpreted function symbols for this purpose. PDPs extend datalog not only with, constructs to specify which predicate is to he optimized and the criterion for optimization but also with constructs to specify which predicate to be relaxed and the criterion to be used for relaxation. We can show that all of the soft requirements in Reference(10)) can be directly encoded in PDP. We first develop a naivety-pruned bottom-up evaluation procedure that is sound and complete for computing answers to normal and relaxation queries when the PDPs are stratified, we then show how the evaluation scheme can be extended to the case when the programs are not necessarily stratified, and finally we develop an extension of the magic templates mettled for datalog(14)) that constructs an equivalent but more efficient program for bottom-up evaluation.
Construction of functionalized indans by thallium(III) promoted ring contraction of 3-alkenols
作者:Helena M.C Ferraz、Luiz F Silva
DOI:10.1016/s0040-4020(01)01021-3
日期:2001.12
Reformatsky reaction with bromo-esters (ethyl 2-bromopropionate, ethyl bromoacetate or ethyl 2-bromobutyrate), followed by dehydration of the β-hydroxy-ester formed. Reduction of the ester moiety led to homoallylic alcohols bearing an endocyclic double bond. The oxidative rearrangement of these 3-alkenols was performed by thallium trinitrate (TTN) in a 2:1 mixture of AcOH/H2O, leading to the ring contraction
开发了一种有效的四步方案,用于功能化茚满的构建。通过与溴酸酯(2-溴丙酸乙酯,溴乙酸乙酯或2-溴丁酸乙酯)的Reformatsky反应,将1-Tetralones转化为不饱和酯,然后将所形成的β-羟基酯脱水。酯部分的还原导致带有内环双键的均烯丙基醇。这些3-烯醇的氧化重排是通过三硝酸th(TTN)在AcOH / H 2 O的2:1混合物中进行的,导致环收缩产物的产率适中至非常好。研究了该序列的十四个例子。还研究了用TTN氧化由2-四氢萘酮制备的3-链烯醇。对于这些底物,未观察到环收缩反应。
Amination of Arenes through Electron-Deficient Reaction Cascades of Aryl Epoxyazides
作者:Stuart Lang、Alan R. Kennedy、John A. Murphy、Andrew H. Payne
DOI:10.1021/ol035319d
日期:2003.10.1
[reaction: see text] Aryl epoxyazides undergo efficient electron-deficient reaction cascades mediated by Lewis acids, leading to regiospecific amination of the aromatic ring.