Stereoselective Synthesis of Substituted γ-Butyrolactones by the [3 + 2] Annulation of Allylic Silanes with Chlorosulfonyl Isocyanate: Enantioselective Total Synthesis of (+)-Blastmycinone
摘要:
[GRAPHICS]A stereoselective synthesis of gamma -butyrolactones by the [3 + 2] annulation of allylic silanes with N-chlorosulfonyl isocyanate (CSI) was developed. An enantioselective total synthesis of (+)-blastmycinone was accomplished using this annulation as the key step.
[reaction: see text] An efficientsynthesis of the tricyclic A-B subunit 2 of angelmicin B is described. A formal three-component coupling of aldehydes 4 and 6 with gamma-silylallylborane 7 was employed to assemble the tetrahydrofuranyl core of 2, a strategy highlighted by the stereoselective [3 + 2] annulation of allylsilanes 5a/5b with aldehyde 4. The efficiency of the [3 + 2] annulation was greatly improved
Friedel–Crafts alkylation of benzene with (polychloromethyl)silanes
作者:Bok Ryul Yoo、Jeong Hyun Kim、Bong Gwan Cho、Il Nam Jung
DOI:10.1016/s0022-328x(01)00827-0
日期:2001.8
(Trichloromethyl)silanes (m=0, 1; n=3) reacted with excess benzene to give (triphenylmethyl)silanes as major products and the unusual (diphenylmethyl)silanes as minor. It was found that unusual (diphenylmethyl)silanes were formed by the decomposition of (triphenylmethyl)silanes under the reaction condition. In the alkylation to benzene, the reactivity of (polychloromethyl)silanes (Cl3−mMemSiCH3−nCln:
在氯化铝的存在下,(多氯甲基)硅烷(Cl 3- m Me m SiCH 3- n Cl n:m = 0–3;n = 2,3)与过量的苯反应生成(聚苯基甲基)硅烷。此类反应发生在室温(m = 2,3; n = 2)到80°C(m = 0,1; n = 2,3)的温度下,表明反应性随数量(m硅上的供电子甲基)。特别是在硅上带有两个或三个甲基的(二氯甲基)硅烷(m = 2或3; n= 2)在室温下进行烷基化和它们的产物分解。与(二氯甲基)三甲基硅烷的反应在室温下立即发生,不产生(二苯基甲基)三甲基硅烷,而是通过烷基化产物的分解得到二苯基甲烷和三甲基氯硅烷。(三氯甲基)硅烷(m = 0,1; n = 3)与过量的苯反应,得到(三苯基甲基)硅烷为主要产物,而不寻常的(二苯基甲基)硅烷为次要产物。发现在反应条件下通过(三苯基甲基)硅烷的分解形成了不寻常的(二苯基甲基)硅烷。在烷基化为苯的过程中,(聚氯甲基)硅烷(Cl
Development of the [3 + 2] Annulations of Cyclohexenylsilanes and Chlorosulfonyl Isocyanate: Application to the Total Synthesis of (±)-Peduncularine
作者:Claudia W. Roberson、K. A. Woerpel
DOI:10.1021/ja012152f
日期:2002.9.1
The synthesis of (+/-)-peduncularine was accomplished using the [3 + 2] annulation of an allylic silane with chlorosulfonyl isocyanate to assemble the bicyclic core of the alkaloid. The stereochemistry of the annulation product was employed to control the installation of the indolylmethyl side chain at C-7 with complete stereoselectivity.
Synthesis of 1,2-Dioxolanes by Annulation Reactions of Peroxycarbenium Ions with Alkenes
作者:Armando Ramirez、K. A. Woerpel
DOI:10.1021/ol051703u
日期:2005.10.1
The annulation reactions of alkenes with peroxycarbenium ions enable the synthesis of a variety of functionalizable 1,2-dioxolanes. Triethysilyl-protected peroxycarbenium ions proved to be optimal for the annulation reaction. Using this method, plakinic acid analogues can be synthesized in three steps from the corresponding ketone and alkene.
Stereoselective Synthesis of Highly Substituted γ-Lactams by the [3+2] Annulation of α-Siloxy Allylic Silanes with Chlorosulfonyl Isocyanate
作者:Antonio Romero、K. A. Woerpel
DOI:10.1021/ol060596g
日期:2006.5.1
A stereoselective synthesis of gamma-lactams by the [3+2] annulation of alpha-siloxy allylic silanes with N-chlorosulfonyl isocyanate (CISO2NCO) was developed. The use of these allylic silanes allowed for further diastereoselective substitution of the resultant N,O-acetal to give highly substituted gamma-lactams. Oxidation of the silyl group afforded access to complex beta-hydroxy-gamma-lactams.