Stereoselective anti-SN2′ Mitsunobu reaction of α-hydroxy-α-alkenylsilanes
摘要:
A novel silyl group-directed anti-S(N)2' reaction of allylic alcohols under Mitsunobu reaction conditions is described. The Mitsunobu reaction of alpha-hydroxy-alpha-alkenylsilanes with a TBS or TIPS group gave the anti-S(N)2' product, in which regio- and stereochemical outcomes of the reaction depended on the steric bulkiness of the silyl group. (C) 2010 Elsevier Ltd. All rights reserved.
Catalytic Anti-Markovnikov Hydroallylation of Terminal and Functionalized Internal Alkynes: Synthesis of Skipped Dienes and Trisubstituted Alkenes
作者:Melrose Mailig、Avijit Hazra、Megan K. Armstrong、Gojko Lalic
DOI:10.1021/jacs.7b02104
日期:2017.5.24
and functionalized internal alkynes. In this article, we describe the development of the reaction, exploration of the substrate scope, and a study of the reaction mechanism. Synthesis of skipped dienes through the hydroallylation of terminal alkyl and aryl alkynes with simple allyl phosphates and 2-substituted allyl phosphates is described. The hydroallylation of functionalized internal alkynes leads
Titanium-Promoted Cross-Coupling for the Selective Synthesis of Polysubstituted, Conjugated Amides
作者:Vinoth Kumar Chenniappan、Ronald J. Rahaim
DOI:10.1021/acs.orglett.6b02537
日期:2016.10.7
α,β-Unsaturated amides are important buildingblocks and are key structural elements in a number of biologically active natural products. Despite their importance and prevalence, few methods exist to prepare conjugated amides directly and modularly. To address this gap, a titanium-promoted coupling of alkynes and isocyanates has been developed. The method is highly stereoselective, producing only the
Enantioselective Synthesis of Siloxyallenes from Alkynoylsilanes by Reduction and a Brook Rearrangement and Their Subsequent Trapping in a [4+2] Cycloaddition
Two flavors of selectivity: An enantioselective Meerwein–Ponndorf–Verley‐type reduction of alkynoylsilanes by a chiral lithium amide followed by a Brookrearrangement and SE2′ electrophilic substitution provides the title compounds in a one‐pot process. In the case of enynoylsilanes, the generated vinylallenes undergo in situ [4+2] cycloaddition to afford highly functionalized polycyclic compounds
两种选择性:通过手性锂酰胺的对映选择性Meerwein-Ponndorf-Verley型还原炔基硅烷,然后进行Brook重排和S E 2'亲电取代,可在一锅法中得到标题化合物。在烯丙基硅烷的情况下,生成的乙烯基亚烷基会进行原位[4 + 2]环加成反应,以提供具有非常规的面部选择性的高度官能化的多环化合物。
Directing Group-Controlled Hydrosilylation: Regioselective Functionalization of Alkyne
hydrosilylation of unsymmetric alkynes proceeds in a highly regioselective manner with a dimethylvinylsilyl (DMVS) group as the directing group. This hydrosilylation affords a single regioisomer of silylalkenes from propargylic and homopropargylic alcohol derivatives. DMVS also has an accelerating effect that allows group-selective hydrosilylation of the DMVS-attached alkyne prior to that of other alkynes. Combined