Synthesis of enantiomerically pure (R)-2-cycloalken-1-ols using highly enantioselective enzymatic transesterification
摘要:
Optically pure (R)-2-cycloalken-1-ols were synthesized via highly enantioselective lipase-catalyzed transesterification of 2-substituted cycloalkanols.
Chlorierungsreaktionen mit den systemen Pb-IV-acetat-(CH3)3SiCl und Pb-IV-acetat—CH3COCl
作者:E. Zbiral、K. Kischa
DOI:10.1016/s0040-4020(01)82727-7
日期:1969.1
Multiple bonds react with the title systems to give 1,2-dichlorocompounds. 1-Acetoxy-2-chlorocompounds are formed as typical byproducts. The stereochemistry of the addition varies from mainly cis to exclusively trans. Simple ketones give α-monochlorketones in good yields.
Eu(dpm)3 [dpm: dipivaloylmethanate] catalyzes the ring-opening reaction of epoxides with acylhalides affording the corresponding 2-haloalkyl esters. The stereochemical course was confirmed as trans-addition in the case of the reaction of cyclohexene oxide.
Cobalt(II)chloride catalysed cleavage of ethers with acyl halides: Scope and mechanism
作者:Javed Iqbal、Rajiv Ranjan Srivastava
DOI:10.1016/s0040-4020(01)96041-7
日期:1991.5
Cobalt (II) chloride in acetonitrile catalyses the cleavage of a wide variety of ethers with acyl halides under mild conditions to give the corresponding esters in good yields. Acyclic aliphatic ethers are cleaved to the corresponding ester and chlorides whereas the cyclic aliphatic ethers give rise to the ω-chloroesters. The benzyl ethers can be converted to the corresponding esters along with the
乙腈中的氯化钴(II)在温和的条件下催化多种醚与酰基卤的裂解,从而以高收率得到相应的酯。无环脂族醚裂解成相应的酯和氯化物,而环脂族醚产生ω-氯代酯。苄基醚可与苄基氯和苄基乙酰胺一起形成相应的酯。烯丙基和苄基醚裂解的比较研究表明,苄基醚可以在烯丙基醚存在下选择性裂解。可以以高度区域选择性的方式将环氧乙烷酮裂解为相应的β-氯代酯。乙烯基醚经历sp 2在这些条件下的-杂化的碳-氧键裂解。基于产物分析,讨论了涉及电子转移,随后进行O-酰化以及氯离子对S N 1或S N 2的攻击的机理。
Preparation and characterization of magnetically separable MgFe<sub>2</sub>
O<sub>4</sub>
/Mg(OH)<sub>2</sub>
nanocomposite as an efficient heterogeneous catalyst for regioselective one-pot synthesis of β-chloroacetates from epoxides
Magneticallyseparable MgFe2O4/Mg(OH)2 nanoparticles were fabricated and characterized using various techniques. These nanoparticles were used as a new catalyst for regioselective one‐pot synthesis of β‐chloroacetates fromepoxides in the presence of NiCl2⋅6H2O and acetic anhydride. All reactions were carried out in ethanol at room temperature within 22–80 min giving the β‐chloroacetates in high to
磁分离MgFe 2 O 4 / Mg(OH)2纳米粒子的制备和表征使用各种技术。这些纳米颗粒被用作用于从氯化镍的存在下环氧化物区域选择性一锅合成β-氯乙酸的新的催化剂2 ⋅6H 2 O和乙酸酐。所有反应均在室温下于乙醇中进行22–80分钟,从而使β-氯乙酸盐的收率高至优异。使用外部磁体可以轻松分离纳米催化剂,并重复使用几次,而不会明显降低效率或磁性。
Intermolecular Halogenation/Esterification of Alkenes with <i>N</i>
-Halosuccinimide and Acetic Acid Catalyzed by 1,4-Diazabicyclo[2.2.2]octane
作者:Laura S. Pimenta、Elena V. Gusevskaya、Eduardo E. Alberto
DOI:10.1002/adsc.201700117
日期:2017.7.3
organocatalyst in the activation of N-chlorosuccinimide (NCS) towards the chlorination of alkenes. The chloriranium ion formed from NCS and the alkene, can be intermolecularly opened by a nucleophile, such as acetic acid, to produce highly functionalized trans-chloro esters in high yields. The protocol is also applied to the synthesis of chlorohydrins and chloro ethers using water or methanol as nucleophiles