LiOtBu was found to efficiently promote the α-alkylation reaction of ketones with primary alcohols, without the addition of any transition metal catalyst.
LiOtBu被发现能高效促进酮与伯醇的α-烷基化反应,无需添加任何过渡金属催化剂。
Manganese-Catalyzed β-Alkylation of Secondary Alcohols with Primary Alcohols under Phosphine-Free Conditions
作者:Tingting Liu、Liandi Wang、Kaikai Wu、Zhengkun Yu
DOI:10.1021/acscatal.8b01960
日期:2018.8.3
secondary alcohols with primary alcohols under phosphine-free conditions. The β-alkylated secondary alcohols were obtained in moderate to good yields with water formed as the byproduct through a borrowinghydrogen pathway. β-Alkylation of cholesterols was also effectively achieved. The present protocol provides a concise atom-economical method for C–C bond formationfrom primary and secondary alcohols.
herein an unprecedented highly efficient Guerbet‐type reaction at room temperature (catalytic TON up to >6000). This β‐alkylation of secondary methyl carbinols with primary alcohols has significant advantage of delivering higher‐order secondary alcohols in an economical, redox‐neutral fashion. In addition, the first enantioselective Guerbet reaction has also been achieved using a commercially available
at 140 °C with high yields and unprecedented turnovers. A maximum of 92% yield of the β-alkylated product at 18 400 TON was obtained in the reaction of benzyl alcohol with 1-(4-(trifluoromethyl)phenyl)ethane-1-ol in the presence of 0.005 mol % of (Ph2NNN)NiCl2(CH3CN) and 5 mol % of NaOtBu at 140 °C after 24 h. The reaction exhibits zero-order dependence of rate on catalyst concentration and first-order
我们在此报告了一系列类型为 ( R2 NNN)NiCl 2 (CH 3 CN) (R = i Pr、t Bu、Cy、Ph 和p -FC 6 H 4 )的 NNN 钳形镍配合物的合成和表征) 基于双(亚氨基)吡啶配体。在溶液中,这些配合物被发现是分别含有一个和两个钳状配体的平衡混合物。虽然我们最近报道了前者的晶体结构 R = i Pr,但我们在本研究中报告了后者的晶体结构 R = p -FC 6 H 4. 所考虑的 NNN 钳形镍配合物已成功用于在 140°C 下以高产率和前所未有的周转率完成几种仲醇与各种苄醇的催化 β-烷基化。在苯甲醇与 1-(4-(三氟甲基)苯基)乙烷-1-醇在 0.005 mol% ( Ph2 NNN)NiCl 2 (CH 3 CN) 和 5 mol % NaO tBu 在 140 °C 后 24 小时。该反应表现出速率对催化剂浓度的零级依赖性和对碱、苯甲醇和 1-苯
Ligand-free Guerbet-type reactions in air catalyzed by <i>in situ</i> formed complexes of base metal salt cobaltous chloride
benign cobaltouschloride efficiently accomplishes the catalytic β-alkylation of alcohols in air at 140 °C. At higher loadings of cobaltouschloride (1 mol%) in the presence of 2.5 mol% NaOtBu, there is a rapid formation of heterogeneous Co nanoparticles (NPs) which are apparently sensitive to air and result in poor yields (ca. 25%) of β-alkylated products. In contrast, performing the reaction in an
价格低廉、地球资源丰富且对环境无害的氯化钴可在 140 °C 的温度下有效地在空气中实现醇的催化 β-烷基化。在存在 2.5 mol% NaO t Bu 的情况下,在较高的氯化钴负载量 (1 mol%) 下,会快速形成对空气明显敏感的异质 Co 纳米颗粒 (NPs),导致产率低 ( ca. 25% ) 的 β-烷基化产物。相比之下,在其他相同条件下在氩气气氛中进行反应会导致更高的产率(约44%)。通过在 2.5 mol% NaO t存在下以较低 (0.01 mol%) CoCl 2负载运行可以延迟空气中的异质化和最终活性损失卜在 140 °C。在这些条件下,醇的催化 β-烷基化以高产率(高达 89%)和前所未有的周转率(约8900 年)进行。机理研究表明基于原位生成的醇分子 Co 配合物的催化剂的参与。标记研究为 C-H 活化参与氯化钴催化的 β-烷基化提供了关键证据,KIE 为 1.61