Highly Diastereo‐ and Enantioselective Synthesis of 3,6′‐Bisboryl‐
<i>anti</i>
‐1,2‐oxaborinan‐3‐enes: An Entry to Enantioenriched Homoallylic Alcohols with A Stereodefined Trisubstituted Alkene
作者:Jichao Chen、Evangelos Miliordos、Ming Chen
DOI:10.1002/anie.202006420
日期:2021.1.11
The three boryl groups in the products are properly differentiated and can undergo a variety of chemoselective transformations to produce enantioenriched homoallylic alcohols with a stereodefinedtrisubstitutedalkene.
[2+2] Cycloaddition of 1,3-Dienes by Visible Light Photocatalysis
作者:Anna E. Hurtley、Zhan Lu、Tehshik P. Yoon
DOI:10.1002/anie.201405359
日期:2014.8.18
[2+2] Photocycloadditions of 1,3‐dienes represent a powerful yet synthetically underutilized class of reactions. We report that visiblelight absorbing transition metal complexes enable the [2+2] cycloaddition of a diverse range of 1,3‐dienes. The ability to use long‐wavelength visiblelight is attractive because these reaction conditions tolerate the presence of sensitive functional groups that might
Redox-Neutral Rhodium(III)-Catalyzed Chemospecific and Regiospecific [4+1] Annulation between Indoles and Alkenes for the Synthesis of Functionalized Imidazo[1,5-<i>a</i>]indoles
unit, a redox-neutral rhodium(III)-catalyzed chemo- and regiospecific [4+1] annulation between indoles and alkenes for the synthesis of functionalized imidazo[1,5-a]indoles has been achieved. Internal alkenes employed here can fulfill an unusual [4+1] annulation rather than normal [4+2] annulation/C–Halkenylation. This method is characterized by excellent chemo- and regioselectivity, broad substrate scope
利用嵌入氧化功能/离去基团的内部烯烃作为稀有和非常规的单碳单元,氧化还原中性铑(III)催化的吲哚和烯烃之间的化学和区域特异性[4 + 1]环化,用于合成功能化咪唑并[1,5- a ]吲哚已经实现。这里使用的内部烯烃可以实现不寻常的 [4+1] 环化,而不是正常的 [4+2] 环化/C-H 烯基化。该方法的特点是优异的化学和区域选择性、广泛的底物范围、良好的官能团耐受性、良好的收率和氧化还原中性条件。
Ruthenium-Catalyzed Vinylsilane Synthesis and Cross-Coupling as a Selective Approach to Alkenes: Benzyldimethylsilyl as a Robust Vinylmetal Functionality
作者:Barry M. Trost、Michelle R. Machacek、Zachary T. Ball
DOI:10.1021/ol034463w
日期:2003.5.1
[reaction: see text] Ruthenium-catalyzed alkyne hydrosilylation or silyl-alkyne Alder ene reactions provide entry into benzyldimethylsilyl (BDMS)-substituted alkenes. The BDMS-vinylsilanes are further elaborated through mild palladium-catalyzed cross coupling and show significant stability to intervening synthetic operations, including silyl ether deprotection.
Development of α,α-Disubstituted Crotylboronate Reagents and Stereoselective Crotylation via Brønsted or Lewis Acid Catalysis
作者:Shang Gao、Meng Duan、Qianzhen Shao、K. N. Houk、Ming Chen
DOI:10.1021/jacs.0c04107
日期:2020.10.28
Stereochemical models for BF3·OEt2-catalyzed reactions are proposed to rationalize the Z-selective allyl additions. These reactions generate highly valuable homoallylic alcohol products with a stereodefinedtrisubstitutedalkene unit. The synthetic utility is further demonstrated by the total syntheses of salinipyrones A and B.
报道了 α,α-二取代巴豆基硼酸酯试剂的开发。手性布朗斯台德酸催化不对称醛加成与开发的 E-巴豆基硼试剂产生 (E)-anti-1,2-oxaborinan-3-enes,具有优异的对映选择性和 E-选择性。在 BF3·OEt2 催化下,立体选择性被逆转,并且从相同的 E-巴豆基硼试剂中获得了具有优异 Z-选择性的 (Z)-δ-硼基-抗高烯丙醇。Z-巴豆基硼试剂还参与BF3·OEt2催化的巴豆化反应以提供具有良好Z-选择性的(Z)-δ-硼基-syn-高烯丙醇。DFT 计算确定了观察到的手性布朗斯台德酸催化的不对称烯丙基化的对映选择性和立体选择性的起源。BF3·OEt2 催化反应的立体化学模型被提出来合理化Z-选择性烯丙基加成。这些反应生成具有立体定义的三取代烯烃单元的高价值高烯丙醇产品。Salinipyrones A 和 B 的全合成进一步证明了合成效用。