Synthesis of 3,4-Dimethylidene Oxacycles through Prins-Type Cyclization of Allenylmethylsilanes
作者:Punna Reddy Ullapu、Young Seub Kim、Jae Kyun Lee、Ae Nim Pae、Youseung Kim、Sun-Joon Min、Yong Seo Cho
DOI:10.1002/asia.201100162
日期:2011.8.1
efficient synthesis of 3,4‐dimethylidene oxacycles including oxolanes and oxepanes through Prins‐type cyclization of hydroxy(allenylmethyl)silanes is described. We have shown that 2‐substituted tetrahydrofuran derivatives could be produced by using this strategy although the 5‐endo‐trig cyclization mode is stereoelectronically disfavored. We also applied our method to the stereoselectivesynthesis of 2
Intermolecular Double Prins-Type Cyclization: A Facile and Efficient Synthesis of 1,6-Dioxecanes
作者:Punna Reddy Ullapu、Sun-Joon Min、Satish N. Chavre、Hyunah Choo、Jae Kyun Lee、Ae Nim Pae、Youseung Kim、Moon Ho Chang、Yong Seo Cho
DOI:10.1002/anie.200804576
日期:2009.3.9
Double or nothing: The title reaction converts a range of aromatic aldehydes and allenylmethyl/allyl silanes into 1,6‐dioxecane derivatives in good to excellent yields (see scheme; Ar=aryl, Tf=triflate, THF=tetrahydrofuran, TMS=trimethylsilyl). In addition, the bisdiene product has been transformed into the corresponding tricyclic compound through a Diels–Alder reaction.
不加或不加:标题反应以良好的产率将一系列芳族醛和烯丙基甲基/烯丙基硅烷转化为1,6-二氧杂环己烷衍生物(参见方案; Ar =芳基,Tf =三氟甲磺酸酯,THF =四氢呋喃,TMS =三甲基甲硅烷基) 。此外,通过Diels-Alder反应,双二烯产物已转化为相应的三环化合物。
In-MEDIATED ALLYLATION OF α-KETO ESTERS WITH ALLYL HALIDES<sup>*</sup>
作者:Phil Ho Lee、Kooyeon Lee、Sukbok Chang
DOI:10.1081/scc-100105896
日期:2001.1
The chemoselective reaction of α-keto esters with allyl halides, propargyl bromides, and allenyl bromide using indium metal afforded α-hydroxy-γ,δ-unsaturated esters in good to excellent yields under mild conditions. *This paper is dedicated to Professor Chang Hwan Rhee on the occasion of his 60th birthday.