A Highly Efficient Macrolactonization Method via Ethoxyvinyl Ester
作者:Yusuke Ohba、Mayuko Takatsuji、Kenji Nakahara、Hiromichi Fujioka、Yasuyuki Kita
DOI:10.1002/chem.200801548
日期:2009.3.23
Facile and efficientmacrolactonization of hydroxycarboxylic acid viaethoxyvinylesters (EVEs), which can give 9‐ to 14‐membered macrolactones in good yields, has been developed (see scheme; DCE = 1,2‐dichloroethane). The method is useful for acid‐/base‐sensitive substrates and applicable to the compound with many functional groups.
Highly efficient macrolactonization of ω-hydroxy acids using benzotriazole esters: synthesis of Sansalvamide A
作者:José Antonio Morales-Serna、Ericka Sánchez、Ricardo Velázquez、Jorge Bernal、Eréndira García-Ríos、Rubén Gaviño、Guillermo Negrón-Silva、Jorge Cárdenas
DOI:10.1039/c0ob00161a
日期:——
A facile and mild macrolactonization reaction of ω-hydroxy acids was developed based on the transesterification of benzotriazole esters. Treatment of ω-hydroxy acids with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and 1-hydroxy benzotriazole (HOBT) in chloroform provided macrolactones in excellent yields. The reactions were performed under basic, neutral and acidic conditions using N,N-d
Solid Phase Synthesis of Macrocycles by an Intramolecular Ketophosphonate Reaction. Synthesis of a (<i>dl</i>)-Muscone Library
作者:K. C. Nicolaou、Joaquín Pastor、Nicolas Winssinger、Fiona Murphy
DOI:10.1021/ja980675q
日期:1998.5.1
The authors describe the construction of a muscone library using the powerful intramol. ketophosphonate-aldehyde condensation reaction. This adds another chem. to the solid-phase reactionlibrary and demonstrates its power in the synthesis of natural products.
We describe a method for the α-selective glycosidation of 3-deoxy-d-manno-2-octulosonic acid (Kdo) using a macrobicyclic Kdo donor as the precursor of a bridgehead oxocarbenium ion, whose stereoselectivity is not affected by the substrate structure and reaction conditions. Strapping Kdo via tethering in the α-configuration at the C1 and C5 positions completely blocked nucleophilic attack to the β-face
a macrobicyclic donor tethered at the C1 and C5 positions. In this study, to expand the scope of Kdo glycosidation, we sought to protect the 4-OH group, thereby shortening the reaction time and ensuring the conversion of the glycosyl acceptor via its selective removal. The protection of the 4-OH group influenced the reactivity of the Kdo donor, and the triisopropylsilyl (TIPS) group acted as a selectively
化学合成含 3-deoxy-d-manno-2-octulosonic acid (Kdo) 的聚糖,如细菌脂多糖 (LPS) 和荚膜多糖 (CPS),对开发针对病原菌的疫苗有很高的需求。我们最近使用拴在 C1 和 C5 位置的大双环供体实现了 Kdo 的完整 α-立体选择性糖苷化。在这项研究中,为了扩大 Kdo 糖苷化的范围,我们试图保护 4-OH 基团,从而缩短反应时间并通过选择性去除确保糖基受体的转化。对4-OH组的保护影响了KDO供体的反应性,而三异丙基硅烷基(TIPS)组充当了可移动的助推器。4-O-TIPS 供体允许合成 α(2,4)-连接的二聚体 Kdo 序列,