Ylide - Wikipedia
网页An ylide (/ ˈɪlaɪd /) [1] or ylid (/ ˈɪlɪd /) is a neutral dipolar molecule containing a formally negatively charged atom (usually a carbanion) directly attached to a heteroatom with a formal positive charge (usually nitrogen, phosphorus or sulfur), and in which both atoms have full octets of electrons.
𬭩内盐 - 维基百科，自由的百科全书
网页鎓内盐 （英語： ylide 或 ylid，音： / ˈɪlɪd /），又音译作 叶立德，指的是一类在相邻原子上有相反电荷的中性 分子。 鎓内盐在 有机化学，尤其是 有机合成 中有很多应用。 一般来说，鎓内盐能以 共振式 表示，其中一个 共振杂化体 具有 双键： 实际的电子分布取决分子的具体性质。 类型. 最常见的鎓内盐是 磷鎓内盐。 维蒂希反应 中即是用磷鎓内盐与 羰基化合物 反应制得 烯烃。 通常 磷 上的正电荷被三个取代的 苯基 所稳定，而 碳 则与两个 烷基 相 …
叶立德（化学物质）_百度百科
网页叶立德（Ylide），又称鎓内盐， 指由供电子的Lewis结构（类似于配位键）形成的正负电荷处于邻位，且均满足八电子结构的内盐分子。 通常地，叶立德可以写成共振式，其中一个共振杂化体具有 双键。 1953Wittig [4]和Giessler发现二苯酮和亚甲基三苯膦作用，得到几乎定量的不对称二苯乙烯。 这个发现立即引起了合成有机化学家的重视，称之为Wittig 反应。 中文名. 叶立德. 外文名. Ylide. 别 名. 鎓内盐. 组 成. 磷叶立德等. 学 科. 化学. 属 性. 盐. 目录. …
Ylide - Chemistry LibreTexts
网页2022年2月28日 · A ylide is a neutral species in which there is a carbon atom bearing a formal charge of -1 bound to a heteroatom bearing a formal charge of +1. Ylides are classified based on the nature of the ….
Ylide - an overview | ScienceDirect Topics
网页A ylide is defined as a neutral dipolar molecule with a negatively charged atom directly attached to a positively charged heteroatom. It serves as a versatile building block in organic synthesis, enabling various reactions like cyclization and olefination. AI generated definition based on: Tetrahedron Letters, 2014. About this page. Add to Mendeley
Ylide Addition - Chemistry LibreTexts
网页2023年1月23日 · Ylides are compounds that are often depicted with a positive charge one one atom and a negative charge on the next atom. They are examples of zwitterions, compounds that contain both positive and negative charges within the same molecule.
Mononuclear Ylide Complexes, Ylide Formation and Examples of …
网页Ylides are compounds in which two neighbouring atoms have complete octet electronic configurations and opposing charges. Ylides are a type of zwitterion, which are charged molecules with both positive and negative charges.
Recent Advances in the Chemistry of Ylides - ScienceDirect
网页1983年1月1日 · Ylides are electrically neutral overall and they can be regarded as a special type of zwitterion in which the structure, or at least one canonical form, contains positive and negative charges on adjacent atoms. This definition excludes classification of the zwitterionic forms of amino acids 6 as ylides.
IUPAC - ylides (Y06728)
网页2014年2月24日 · Compounds in which an anionic site Y− (originally on carbon, but now including other atoms) is attached directly to a heteroatom X+ (usually nitrogen, phosphorus or sulfur) carrying a formal positive charge. They are …
Reactions of Ylides - Chemistry LibreTexts
网页2023年1月23日 · The most important use of ylides in synthesis comes from their reactions with aldehydes and ketones, which are initiated in every case by a covalent bonding of the nucleophilic alpha-carbon to the electrophilic carbonyl carbon. Alkylidenephosphorane ylides react to give substituted alkenes in a transformation called the Wittig reaction. This ...