Gold Catalysis: Efficient Synthesis and Structural Assignment of Jungianol andepi-Jungianol
作者:A. Stephen K. Hashmi、Li Ding、Jan W. Bats、Peter Fischer、Wolfgang Frey
DOI:10.1002/chem.200305092
日期:2003.9.22
Starting from 2-methylfuran and crotonaldehyde, both jungianol and epi-jungianol were prepared by a six-step sequence including a gold-catalyzed arene synthesis and a photochemical S(N)2-like reduction with lithium aluminum hydride. Not a single protective group was needed in the entire synthesis. With both diastereomers in hand, the stereochemicalassignment in the literature could be corrected by
One-Pot, Three-Step Synthesis of Cyclopropylboronic Acid Pinacol Esters from Synthetically Tractable Propargylic Silyl Ethers
作者:Jonathan A. Spencer、Craig Jamieson、Eric P. A. Talbot
DOI:10.1021/acs.orglett.7b01778
日期:2017.7.21
propargylic silyl ethers can be converted to complex cyclopropylboronic acid pinacol esters in an efficient one-pot procedure. Terminal acetylenes undergo a Schwartz’s reagent catalyzed hydroboration; subsequent addition of further Schwartz’s reagent and Lewis acid-mediated activation of neighboring silyl ether allows cyclization to access a range of cyclopropylboronic acid pinacol esters. The scope includes
Direct C–C Bond Formation of Allylic Alcohols with CO<sub>2</sub> toward Carboxylic Acids by Photoredox/Nickel Dual Catalysis
作者:Zhengning Fan、Shenhao Chen、Song Zou、Chanjuan Xi
DOI:10.1021/acscatal.2c00418
日期:2022.3.4
Carboxylation of allylic alcohols with carbondioxide is accomplished by photoredox/nickel dual catalysis, generating linear acids exclusively with good Z/E stereoselectivity. Hantzsch ester is employed as the reductant instead of stoichiometric metallic reductants, and the reaction can be conducted under room temperature with a blue LED light source. Mechanisticstudies reveal that the presence of
烯丙醇与二氧化碳的羧基化是通过光氧化还原/镍双重催化完成的,仅生成具有良好Z/E立体选择性的线性酸。采用 Hantzsch 酯代替化学计量的金属还原剂作为还原剂,反应可以在室温下用蓝色 LED 光源进行。机理研究表明,该催化体系中水的存在对反应的成功至关重要,并且反应更有可能在原位形成的烯丙基碳酸氢盐的氧化加成中进行。
Synthesis of allenyl-B(MIDA) via hydrazination/fragmentation reaction of B(MIDA)-propargylic alcohol
作者:Jiasheng Qian、Zhi-Hao Chen、Yuan Liu、Yin Li、Qingjiang Li、Shi-Liang Huang、Honggen Wang
DOI:10.1016/j.cclet.2022.04.077
日期:2023.1
challenging to synthesis. In addition, these compounds are typically unstable, rendering the separation difficult. We report herein a practical and concise route to a new class of stable, easy-separable allenyl B(MIDA) via a hydrazination/fragmentation of B(MIDA)-propargylic alcohols. The synthesis of optically active allenyl B(MIDA) was also achieved. Interesting reactivity of the resulting product was