内酯直接氢解为羧酸(即不接触羰基的C烷氧基-O键的氢解)通常是困难的,因为当前使用布朗斯台德酸作为催化剂的策略通常需要苛刻的条件,例如高温和高温H 2压力。在此,我们报告了已开发的无溶剂催化转化方法,其中W(OTf)6被认为可以促进氢解过程。该策略可以在特别温和的条件下(例如,反应温度<150°C和1 atm H 2的条件下)有效地将内酯氢化为羧酸),并显示出较宽的基材范围。另外,该催化方案可以进一步应用于作为可再生聚合物的聚羟基链烷酸酯的氢解成相应的直链羧酸。随后进行了广泛的机理研究,密度泛函理论计算揭示了一种反应模式,包括在W(OTf)6的帮助下C═O键的完全裂解催化剂。此外,通过电喷雾电离质谱已成功检测到该机理中产生的关键中间体,即具有OTf部分的moiety。通过与布朗斯台德酸催化体系的比较,研究证实了OTf部分的存在可以显着降低与重排和消除过程相关的障碍。同时,重点放在阴离子发挥
Stereoselective Synthesis of δ-Lactones from 5-Oxoalkanals via One-Pot Sequential Acetalization, Tishchenko Reaction, and Lactonization by Cooperative Catalysis of Samarium Ion and Mercaptan
作者:Jue-Liang Hsu、Jim-Min Fang
DOI:10.1021/jo016058t
日期:2001.12.1
sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis
[EN] KETAL ESTERS OF ANHYDROPENTITOLS AND USES THEREOF<br/>[FR] CÉTO-ESTERS D'ANHYDROPENTITOLS ET LEURS UTILISATIONS
申请人:XLTERRA INC
公开号:WO2010138842A1
公开(公告)日:2010-12-02
The present disclosure relates to the preparation of ketal compounds from anhydropentitols and oxocarboxylates; derivatives, homopolymers, and copolymers thereof; and various compositions, formulations, and articles derived therefrom.
hydroacyloxylation of unactivated alkenes, offering a streamlined access to relevant γ-lactones, which features the utilization of either a calcium(II) salt or triflimide as a catalyst in hexafluoroisopropanol. This method could be applied to the synthesis of natural products and the late-stage functionalization of natural and bioactive molecules. Additionally, DFT computations were used to elucidate the twist
One-Pot Bi(OTf)3-Catalyzed Oxidative Deprotection of tert-Butyldimethyl Silyl Ethers with TEMPO and Co-Oxidants
作者:Jean-Michel Vatèle、Bogdan Barnych
DOI:10.1055/s-0030-1260980
日期:2011.9
A sequential one-pot synthesis for the oxidation of primary and secondary tert-butyldimethylsilyl (TBDMS) ethers, using catalytic amounts of metal triflates and TEMPO in combination with PhIO or PhI(OAc)2 in THF or acetonitrile, is described. Acid-sensitive protecting groups such as methylidene, isopropylidene, acetals, and Boc are unaffected under the reaction conditions. Another feature of this procedure
THIOPYRANOSE COMPOUND AND METHOD FOR PRODUCING SAME
申请人:FUJIFILM Corporation
公开号:US20160355497A1
公开(公告)日:2016-12-08
There is provided a production method of a thiopyranose compound represented by the following Formula (2) by reacting a compound represented by the following Formula (1) with a sulfur compound.
X represents a leaving group. A represents an oxygen atom or a sulfur atom. Further, each of R
1A
to R
4B
, R
1B
to R
4B
, and R
5
represents a hydrogen atom or a specific substituent.