One-Pot Conversion of α,β-Unsaturated Alcohols into the Corresponding Carbon-Elongated Dienes with a Stable Phosphorus Ylide−BaMnO4 System. Synthesis of 6‘-Methylene Derivatives of Neplanocin A as Potential Antiviral Nucleosides. New Neplanocin Analogues. 111
One-Pot Conversion of α,β-Unsaturated Alcohols into the Corresponding Carbon-Elongated Dienes with a Stable Phosphorus Ylide−BaMnO4 System. Synthesis of 6‘-Methylene Derivatives of Neplanocin A as Potential Antiviral Nucleosides. New Neplanocin Analogues. 111
复制标题
使用稳定的磷叶立德-BaMnO4 系统将 α,β-不饱和醇一锅转化为相应的碳延长二烯，合成 Neplanocin A 的 6-亚甲基衍生物作为潜在的新 Neplanocin 核苷。
DOI：
10.1021/jo971374m
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发表时间：
1998
影响因子：
3.6
通讯作者：
A. Matsuda
中科院分区：
文献类型：
--
作者：
S. Shuto;S. Niizuma;A. Matsuda
维蒂希反应是一种从羰基衍生物形成烯烃的高度通用的方法。 2 利用维蒂希反应的例子如方案1所示：R1-不饱和醇(I)的氧化，3其中羟基R位上的CH键被相邻的π键“活化”，随后所得R1-不饱和醛(II)进行维蒂希反应，得到相应的二烯衍生物(III)。这种类型的过程通常可用于构建有机合成化学中的碳延长二烯结构。在本文中，我们描述了一种有效的一锅法，通过稳定的磷叶立德-BaMnO4系统将R1-不饱和醇(I)转化为相应的碳延长的二烯产物(III)。由于碳环核苷的生物学重要性，最近引起了相当多的关注。 4 我们之前对奈普拉诺星 A (NPA, 1)（一种碳环核苷抗生素）进行了化学修饰，以开发有效的抗病毒药物。 6 在这些研究中，我们发现 neplanocin A 的一些 6' 修饰类似物，例如(6' R)-6'-C-methylneplanocin A (RMNPA, 2) 和 6'-homoneplanocin A (HNPA, 3)，显示出显着的抗病毒活性。在研究过程中，我们还需要 NPA 的 6'-亚甲基衍生物，例如 4 和 5。制备这些化合物的直接方法是如方案 1 所示。因此，我们通过各种方法检查了 6 的氧化情况，7 和 6'-甲酰基衍生物 7 仅当 6 用 BaMnO4 处理时才产生，8 已知是在 CH2Cl2 中将伯烯丙醇氧化为醛的有用氧化剂（方案2）。由于其不稳定性，醛7无需纯化即可立即用Ph3PdCHCO2Et处理，得到所需的产物
Wittig reaction is a highly versatile method for forming alkenes from carbonyl derivatives. 2 An example of utilizing Wittig reaction is shown in Scheme 1: oxidation of R,-unsaturated alcohols (I), 3 in which the CH bonds at the R-position of the hydroxyl group are “activated” by an adjacent π-bond, and subsequent Wittig reaction of the resulting R,-unsaturated aldehydes (II) gives the corresponding diene derivatives (III). This type of procedure is often useful for constructing carbon-elongated diene structures in synthetic organic chemistry. In this paper, we describe an efficient one-pot method for converting R,-unsaturated alcohols (I) into the corresponding carbon-elongated diene products (III) with a stabilized phosphorus ylide-BaMnO4 system. Considerable attention has recently been focused on carbocyclic nucleosides because of their biological importance. 4 We previously performed chemical modifications of neplanocin A (NPA, 1), 5 a carbocyclic nucleoside antibiotic, to develop potent antiviral agents. 6 In these studies, we found that some 6′-modified analogues of neplanocin A, eg,(6′ R)-6′-C-methylneplanocin A (RMNPA, 2) and 6′-homoneplanocin A (HNPA, 3), showed significant antiviral activities. During the course of the study, we further needed 6′-methylene derivatives of NPA, such as 4 and 5. A straightforward method for preparing these compounds would be that as indicated in Scheme 1. Thus, we examined the oxidation of 6 by various methods, 7 and the 6′-formyl derivative 7 was produced only when 6 was treated with BaMnO4, 8 which is known to be a useful oxidant of primary allylic alcohols to aldehydes, in CH2Cl2 (Scheme 2). Due to its instability, the aldehyde 7 was immediately treated with Ph3PdCHCO2Et without purification to give the desired