Catalytic Enantioselective Carbon–Oxygen Bond Formation: Phosphine-Catalyzed Synthesis of Benzylic Ethers via the Oxidation of Benzylic C–H Bonds
作者:Daniel T. Ziegler、Gregory C. Fu
DOI:10.1021/jacs.6b08486
日期:2016.9.21
Benzylic alcohols and ethers are common subunits in bioactive molecules, as well as useful intermediates in organic chemistry. In this Communication, we describe a new approach to the enantioselective synthesis of benzylic ethers through the chiral phosphine-catalyzed coupling of two readily available partners, γ-aryl-substituted alkynoates and alcohols, under mild conditions. In this process, the
Chiral phosphine-catalyzed tunable cycloaddition reactions of allenoates with benzofuranone-derived olefins for a highly regio-, diastereo- and enantioselective synthesis of spiro-benzofuranones
作者:De Wang、Guo-Peng Wang、Yao-Liang Sun、Shou-Fei Zhu、Yin Wei、Qi-Lin Zhou、Min Shi
DOI:10.1039/c5sc03135d
日期:——
The first regioselective catalytic asymmetric [3 + 2] cycloaddition of benzofuranone-derived olefins with allenoates and substituted allenoates has been developed in the presence of (R)-SITCP.
An effective Lewis base catalyst-controlled α-regioselective annulation reaction of γ-substituted allenoates with unsaturated pyrazolones has been developed, affording various spiro-cyclopentene-pyrazolones and pyrano[2,3-c]pyrazoles. The combination of PPh3 and K2CO3 promoted the [3+2] annulation to access the spiro-cyclopentene-pyrazolones in moderate to good yields (up to 90%) with excellent di
已经开发出有效的路易斯碱催化剂控制的γ-取代的烯酸酯与不饱和吡唑酮的α-区域选择性环化反应,提供了各种螺-环戊烯-吡唑酮和吡喃并[2,3-c]吡唑。PPh 3和K 2 CO 3的组合促进了[3 + 2]环化反应,以中等至良好的产率(高达90%)具有优异的非对映选择性(dr> 19:1)进入螺环戊烯-吡唑啉酮。通过使用DBU作为催化剂成功地实现了生成吡喃并[2,3-c]吡唑的4 + 2]环化反应(产率高达92%)。重要的是,使用我们以前报道的手性二茂铁基膦催化剂可以实现螺环-环戊烯-吡唑啉酮的不对称合成。
Phosphine-catalyzed [3 + 2] annulation reaction: highly regio- and diastereoselective synthesis of 2-azaspiro[4.4]nonene-1,3-diones
A novel phosphine-catalyzed [3+2] annulation of γ‑substituted allenoates with succinimides was developed, which was successfully applied to the synthesis of 2-azaspiro[4.4]nonenes-1,3-dione derivatives. The reaction afforded the desired products in moderate to high yields (up to 96%) with excellent regioselectivities and diastereoselectivities (up to >99 : 1 dr). A plausible reaction mechanism has
Redox Isomerization/(3+2) Allenoate Annulation by Auto‐Tandem Phosphine Catalysis
作者:Jeremy T. Maddigan‐Wyatt、Mitchell T. Blyth、Jhi Ametovski、Michelle L. Coote、Joel F. Hooper、David W. Lupton
DOI:10.1002/chem.202103224
日期:2021.11.22
mediates the redox isomerization of amino crotonates to give imines which then undergo (3+2) annulation with a range of allenoates in a second phosphine catalyzed process. Computational studies indicate that pivotal to the success of this reaction is the use of catalysts with similar ability to add to both allenoate and crotonate.