Advances in Reactions of Iodonium Ylides

Abstract

( a 东北师范大学化学学院 长春 130024)

Radionuclide-labeled boron delivery agents

“…碘叶立德是碘鎓离子的 一类, 其中碳以碳负离子形式存在. 芳基碘叶立德可以 利用对应的高价碘芳环化合物与活性亚甲基化合物在 碱性条件下制备 [27] , 研究推测其实现氟化反应的机理 是由碘叶立德发生质子化反应后, 氟离子进攻发生取 代反应得到氟代芳烃 [28] . 王璐 [29] 采取对多种高价碘叶立德前体进行放射化 学反应得到[…”

Sulfur-Mediated Formal Allylic C–H Cyclopropanation of α-Methylstyrenes

“…Vinyl cyclopropanes are also versatile synthetic intermediates, which might rearrange to cyclopentenes, or undergo various annulation reactions (Figure b) . Besides traditional methods such as Simmons–Smith reactions, Michael-initiated ring closure reactions, diazo derived metal carbene cyclopropanation reactions, and cationic cyclopropanation, transition metal catalyzed C–H functionalization recently emerged as a more direct route to access these compounds. In 2006, the Yu group applied the palladium catalyzed C–H iodination reaction to prepare cyclopropane rings via radical cyclization of diiodide intermediates (Scheme a), and their oxazoline directing group containing products could be hydrolyzed to give cyclopropyl substituted carboxylic acids.…”

Rh(III)-Catalyzed C–H Annulation of Alkenyl- or Arylimidazoles and (Hetero)cyclic 1,3-Dicarbonyl Compounds: A Rapid Access to Imidazo-Fused Polycyclic Compounds

“…A plausible mechanism is proposed in Scheme on the basis of the previous literature reports ,− and our preliminary mechanistic exploration . First, reaction of a heterocyclic 1,3-dicarbonyl compound 5 and HFIP gives piperidine-2,4-dione 5′ , which reacts with PhI­(OAc) 2 , producing the iodonium ylide intermediate B . Meanwhile, the rhodacycle intermediate A is achieved by the concerted metalation–deprotonation (CMD) of 2-phenyl-1 H -imidazole and active Cp*Rh III catalyst, which follows subsequent coordination of the intermediate B to generate a carbene intermediate C via the loss of iodobenzene.…”