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An Improved Method of Total Synthesis of 2-Methoxypodocarpane-8,11,13-triene

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Chinese Chemical Letters 2001年第3期12卷 197-198页

作者： Qiang XIAO Yu Xin CUI Peng Fei TU Department of Natural Medicines School of Pharmaceutical SciencesPeking UniversityBeijing 100083 Department of Chemistry Lanzhou UniversityLanzhou 730000

12-Methoxypodocarpane-8,11,13-triene 1, the key intermediate in the synthesis of some important diterpenes, was synthesized in an efficient way, which has the characteristics of short route simple operation and high y... 详细信息

关键词： Synthesis diterpenes 12-methoxypodocarpane-8 11 13-triene cyclization.

Regioselective and Stereoselective Synthesis of the 3-Aryl-4- phosphoryl-1, 2, 4-triazoline-5-ones

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Chinese Chemical Letters 2006年第9期17卷 1145-1148页

作者： De Xin FENG Ru Yu CHEN You HUANG Institute of Elemento-Organic Chemistry National Key Laboratory of Elemento-Organic Chemistry Nankal University Tianjin 300071

A novel and efficient route of synthesizing 1, 2, 4-triazoline-5-ones is reported. The title compounds can be prepared in high yield and purity by the one-pot oxidation and cyclization.of 1-acylthiosemicarbazides. The... 详细信息

关键词： Triazoline 1-acylthiosemicarbazides regioselective stereoselective cyclization.

New Processes for Annulation

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合成化学 2004年第Z1期12卷 18-18页

作者： Liu Hsing-Jang Department of Chemistry Tsing Hua University Hsinchu Taiwan 30013

Making use of the high propensity of 2-cyano-2-cycloalkenones to undergo conjugate addition with various carbanions and the high reactivity of the ensuing α -cyano ketone system, a number of new annulation processes have been developed recently in our laboratories. As shown in Eq. 1 (n=1) with a specific example, one such process involves the addition of 3-butenylmagnesium bromide, followed by a palladium (Ⅱ) acetate mediated oxidative cyclization. to facilitate methylenecyclopentane ring formation. This annulation process could be readily extended to effect methylenecyclohexane ring formation (Eq. 1, n=2), using 4-pentenylmagnesinm bromide as the initial reagent, and to install the carbomethoxy-substituted methylenecyclopentane and methylenecyclohexane rings, using the carbanions derived from methyl 4-pentenoate and methyl 5-hexenoate, respectively (Eq. 2). In another annulation process, the addition of the enolate of methyl 5-chloropentanoate is involved initially, and the ring formation is readily effected by an intramolecular alkylation process. A specific example is given in Eq. 3.

关键词： annulation, 2-cyano-2-cycloalkenones, conjugate addition, cyclization.