Chemo-, regio-, and stereoselective hydroboration of conjugated enyne alcohol/amine: facile synthesis of Z , Z -/ Z , E -1,3-dien-1/2-ylboronic ester bearing hydroxyl/amino group
Hydroboration of conjugated enyne alcohol/amine is studied by using copper salts and bis(pinacolato)diboron as pre-catalysts and boron source respectively. It is suggested that the chemo-selectivity is derived from a combined electronic influence of the heteroatoms on the substrate and the ligand on the transition metal. The regioselectivity is probably dominated mainly by electronic effect of the
ONE-POT OXIDATION AND WITTIG OLEFINATION OF ALCOHOLS USING O-IODOXYBENZOIC ACID AND STABLE WITTIG YLIDE<sup>*</sup>
作者:Arup Maiti、J. S. Yadav
DOI:10.1081/scc-100104061
日期:2001.1
Benylic, allylic, and propargylic alcohols, as well as diols, can be oxidized with o-iodoxybenzoic acid (IBX) in the presence of stabilized Wittig ylide[1] to generate α,β-unsaturated ester in one pot. This is useful when the intermediate aldehydes are unstable and difficult to isolate. *IICT communication no. 4369.
Ethyl 3-chloro-3-(3, 4-dichlorophenylthio)propanoate (8) reacted with electron-rich arenes in the presence of titanium tetrachloride to give the Friedel-Crafts products 10a-13a. Reactions of 8 with 1-trimethylsilylalkynes 14a-d were effected with aluminum chloride to afford the substitution products 15a-d. Some chemical transformations of the products are also described.
One-Pot O<sub>2</sub>-Oxidation and the Horner–Wadsworth–Emmons Reaction of Primary Alcohols for the Synthesis of (<i>Z</i>)-α,β-Unsaturated Esters
作者:Kaori Ando、Chika Takaba、Masahiro Kodama
DOI:10.1021/acs.joc.2c00763
日期:2022.8.5
primary alcohols giving Z-α,β-unsaturated esters 3. TEMPO-(CuCl or CuBr2)-(2,2′-bipyridine) (1:1:1) catalyzed O2 oxidation of primary alcohols in the presence of Z-selective Horner–Wadsworth–Emmons reagent 1b and K3PO4 or NaH gave 3 with Z/E = 84:16 to 96:4 in high yields. A stepwise reaction was also developed. After TEMPO-CuBr2-(2,2′-bipyridine)-K3PO4 (1:1:1:1) catalyzed O2 oxidation of alcohols in MeCN
我们开发了伯醇的一锅氧化/烯化程序,得到Z -α,β-不饱和酯3。TEMPO-(CuCl 或 CuBr 2 )-(2,2'-联吡啶) (1:1:1) 在Z选择性 Horner-Wadsworth-Emmons 试剂1b和 K 3 PO 4存在下催化伯醇的 O 2氧化或 NaH以Z / E = 84:16 至 96:4 的高产率得到3 。还开发了逐步反应。TEMPO-CuBr 2 -(2,2'-联吡啶)-K 3 PO 4 (1:1:1:1)催化O 2后在 MeCN 中氧化醇,所得混合物在 -78 °C 至 0 °C 下用1b和t -BuOK 的 THF 溶液处理,得到具有更高选择性的3 ( Z / E = 91:9 至 99:1)。