叔膦参与下联烯酸酯与醛的反应

联烯酸酯是近年来研究较多的一类重要的缺电子联烯,具有丰富的化学反应.本文着重总结了近年来在叔膦参与下(催化或化学计量方式)联烯酸酯与醛的新反应,包括2,3-丁二烯酸酯与醛的成环反应、γ-取代联烯酸酯与醛的[3+2]环加成反应和烯化反应、α-取代联烯酸酯与醛的Vinylogous Wittig反应以及环丙烷化反应,并从反应机理的角度,探讨了联烯酸酯与亲电试剂活化烯、亚胺和醛在反应性上的差异.在这些重要的化学转化中,叔膦的特殊性质如亲核性与夺氧能力起了关键的作用.     

烯丙基磷叶立德与羰基化合物的Vinylogous类型有机反应研究进展

烯丙基磷叶立德(allylic phosphorus ylides)是一类具有丰富反应性的有机中间体.由于碳负离子离域,烯丙基磷叶立德可通过γ位碳负离子参与亲核进攻,从而实现vinylogous(插烯)类型有机合成反应.综述了烯丙基磷叶立德与羰基化合物的vinylogous类型反应,具体包括vinylogous Wittig烯化反应以及多种环化反应.这些反应拓展了烯丙基磷叶立德在有机合成中的应用,并提供构筑多种重要有机功能分子的新方法.     

一种简便合成多取代呋喃的新方法

在三丁基膦和碱的共同作用下,炔酯、芳香醛和酰氯顺利发生四组分串联环化反应,以中等收率生成三或四取代呋喃,反应经原位生成的磷叶立德活性中间体所进行的分子内Wittig反应模式完成,具有反应条件温和及底物范围广的特点,为多取代呋喃的合成提供了简便的新方法.     

膦催化水杨醛亚胺与马来酰亚胺的[4+1]环化反应及螺[苯并呋喃-2,3'-吡咯烷]衍生物的合成（英文）

报道了一个膦催化水杨醛亚胺与马来酰亚胺的[4+1]环化反应,以44%～99%收率生成螺[苯并呋喃-2,3'-吡咯烷]衍生物.产物包含一对可经硅胶柱层析分离的syn和anti异构体(dr 1.6∶1～5∶1),由此提供了合成螺[苯并呋喃-2,3'-吡咯烷]简单有效的方法.该反应起始于PPh_3与马来酰亚胺原位形成非烯丙基磷叶立德活性中间体,经亲核加成/分子内取代的串联过程完成,代表了新的一例经此类磷叶立德完成的膦催化[4+1]环化反应.     

Wittig反应的研究——Ⅴ.亚苄基烷基二苯基膦与取代芳醛的反应

用二苯基烃基型叶立德来研究 Wittig 反应的立体化学将会给人们提供许多有用的信息。我们曾报道,二苯基烯丙基型叶立德与某些醛类在有盐或无盐(锂盐)的条件下所生成的各种1,3-二烯,其 E/Z 值远远大于相应的三苯基叶立德的。根据这一规律,我们曾比较满意     

钯催化下稳定磷叶立德与烯丙基醇的脱水偶联反应

报道了钯催化下酮基稳定的磷叶立德与烯丙基醇一锅法的烯丙化-Wittig反应.研究表明,在5mol%四(三苯基膦)钯和20mol%硼酸的共催化下,以52%～95%的收率得到官能化1,4-二烯化合物.该方法还可以进一步拓展到酯基以及氰基稳定的磷叶立德来合成对应的1,4-二烯化合物.     

亲核叔膦促进的联烯酸酯环加成反应研究进展

20世纪90年代中期,陆熙炎教授报道了亲核叔膦促进的联烯酸酯与缺电子烯烃和亚胺环加成反应.二十年来,作为高效构建功能化碳环及杂环化合物方法,叔膦促进的联烯酸酯环加成反应的发展和应用受到化学家的广泛关注.多样性的亲核叔膦和不同结构联烯酸酯的引入,可呈现多种类型的环加成反应.特别是手性叔膦的应用,高选择性地实现了对该类反应的不对称催化,为一些天然产物和药物模块的全合成开辟了新途径.此外,醛酮化合物也被运用到此类反应中,构建了多种有用的含氧杂环.本篇综述包括六部分:第一部分是引言,概括介绍陆氏反应;第二至五部分分别阐述了亲核叔膦促进联烯酸酯与缺电子烯烃、亚胺、醛酮以及特定亲核试剂的各种环加成反应;最后一部分是总结与展望.     

二苯基甲基烯丙基型膦烷与醛的Wittig反应的立体化学研究

利用3-甲氧基羰基-2-稀丙基二苯基甲基膦叶立德与醛(脂肪醛、芳香醛、杂环醛)的Wittig反应合成了5-取代-2,4-戊二烯酸甲酯(ABA酯类似物),研究了碱对Wittig反应立体化学的影响,发现了该类型季鏻盐的Wittig反应具有很好的4E选择性,并提出了可能的反应机理.     

微波促进立体选择性高效合成糖基α,β-不饱和酯类化合物

利用微波促进糖醛与叶立德(Ph3P=CHCOOEt)发生Wittig反应,立体选择性地合成了含有α,β-不饱和酯的糖烯类化合物,反应效率显著提高,使用不同的反应溶剂可实现对反应立体选择性的控制.并通过1H NMR中双键氢的偶合常数确定了产物的构型.     

手性叔膦-酰胺不对称催化香豆素与Morita-Baylis-Hillman碳酸酯之间的插烯烯丙基烷基化反应（英文）

发展了新型手性双功能叔膦-酰胺催化4-甲基香豆素化合物与外消旋Morita-Baylis-Hillman碳酸酯之间的插烯烯丙基烷基化反应,反应条件温和,底物适用范围广泛.在10～15mol%的基于手性环己烷骨架的叔膦-酰胺催化剂C10作用下,相应产物的产率达到87%～99%,对映选择性最高达98%ee,为手性香豆素衍生物的不对称合成提供了有效的方法.     

Aqueous Wittig Reactions of Aldehydes with In Situ Formed Semistabilized Phosphorus Ylides

The Wittig reactions of three semistabilized phosphorus ylides generated in situ from the corresponding phosphonium salts with aldehydes in water without any organic cosolvent were investigated. Most of the olefination reactions completed within between 5 min and 4.5 h in refluxing water containing 1.5 equiv of LiOH and 1.4 M LiCl to afford the products in 65–100% yields. The E∶Z selectivity depended not only on the substituent attached to the benzene ring of the ylides but also on the substituent bound to the aromatic aldehydes. LiCl promotes the aqueous Wittig reactions and suppresses decomposition of the ylide or the corresponding phosphonium salt.     

PBu3-mediated vinylogous Wittig reaction of α-methyl allenoates with aldehydes and mechanistic investigations

A highly stereoselective PBu(3)-mediated vinylogous Wittig olefination between α-methyl allenoates and a variety of aldehydes is presented as the first example of a practical and synthetically useful vinylogous Wittig reaction. Mechanistic experiments including deuterium-labeling, intermediate entrapment, and NMR monitoring have been deliberately conducted. On the basis of mechanistic investigations, a reliable mechanism for the vinylogous Wittig reaction is proposed, which features a water/phosphine-coassisted allylic phosphorus ylide 1,3-rearrangement pathway, rather than previous retro-Diels-Alder ones. It is noteworthy that mechanistic findings in this work also provide supportive evidence for typical mechanisms of important phosphine-mediated reactions of allenoates.     

Wittig reactions of moderate ylides with heteroaryl substituents at the phosphorus atom

The influence of various heteroaryl substituents at the phosphorus atom to the stereoselectivity of Wittig reactions of allylic and benzylic ylides has been studied. In the case of nitrogen bearing heteroaromatic ligands at the phosphorous atom of benzylidenephosphoranes high E-alkene selectivity's of up to 90:10 could be observed. NMR spectroscopic investigations revealed that substituents at the phosphorus have influences on the reactivity of ylides as well as the stability of reaction intermediates. Indications for chelation of lithium ions with ylides could also be detected and will be discussed in this article.     

Water is an efficient medium for Wittig reactions employing stabilized ylides and aldehydes

Water is demonstrated to be an excellent medium for the Wittig reaction employing stabilized ylides and aldehydes. Although the solubility in water appears to be an unimportant characteristic in achieving good chemical yields and E/Z-ratios, the rate of Wittig reactions in water is unexpectedly accelerated.     

Vinyl Triphenylphosphonium Salt–Mediated Synthesis of Functionalized Alkenes

Deoxybenzoin undergoes a smooth reaction with acetylenic esters in the presence of triphenylphosphine to produce phosphorus ylides. Only the tert-butyl phosphorus ylide undergoes an intramolecular Wittig reaction to produce highly strained cyclobutenes in boiling toluene, which spontaneously undergoes ring-opening reactions to produce highly functionalized 1,3-dienes. The unstable ylides undergo a 1,2-proton transfer and the loss of PPh₃ to produce functionalized alkenes.     

Microwave-Assisted Wittig Reaction of Semistabilized Nitro-Substituted Benzyltriphenyl-Phosphorous Ylides with Aldehydes in Phase-Transfer Conditions

We report here a simple entry into the nitrostilbene system in very short reaction times and good yields using the microwave-assisted Wittig reaction in phase-transfer conditions of nitro-substituted benzyltriphenylphosphonium ylides with aldehydes.     

SYNTHESIS OF HIGHLY ELECTRON-POOR ALKENES FROM IN SITU GENERATED STABILIZED PHOSPHORUS YLIDES AND NINHYDRIN VIA INTERMOLECULAR WITTIG REACTION

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by alcohols leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce the corresponding stabilized phosphorus ylides. Intermolecular Wittig reaction of the stabilized phosphorus ylides with ninhydrin leads to the corresponding, highly electron-poor alkenes.     

One-Step Synthesis of Electron-Poor Alkenes from Triphenylphosphine,Acetylenic Esters, 2,2,2-Trichloroethanol,and Ninhydrin

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 2,2,2-trichloroethanol leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction with a conjugate base to produce the corresponding chlorine-containing stabilized phosphorus ylides. An intermolecular Wittig reaction of the chlorine-containing stabilized phosphorus ylides with ninhydrin leads to the corresponding highly electron-poor chlorine-containing alkenes.     

Organosulfur phosphonium salt-mediated synthesis of functionalized thiopyran derivatives

Methyl 4-oxotetrahydro-2H-thiopyran-3-carboxylate as a CH-acid undergoes a mild reaction with acetylenic esters in the presence of triphenylphosphine to produce phosphorus ylides possessing thiopyran-4-one ring moiety. The resulted phosphorus ylides when heated in toluene afforded functionalized thiopyran derivatives through intramolecular Wittig reaction.