Liquid–Liquid Extraction Protocol for the Removal of Aldehydes and Highly Reactive Ketones from Mixtures
作者:Maria M. Boucher、Maxwell H. Furigay、Phong K. Quach、Cheyenne S. Brindle
DOI:10.1021/acs.oprd.7b00231
日期:2017.9.15
The reaction of the bisulfite ion with aldehydes to form charged bisulfite adducts is a well-established method for the purification of aldehydes. This reaction has been modified to create a convenient liquid–liquid extraction method for the removal of aldehydes from mixtures. The use of a water-miscible solvent allows the reaction to occur during a simple 30 s shaking protocol by increasing the contact
Highly Regio- and Enantioselective Reductive Coupling of Alkynes and Aldehydes via Photoredox Cobalt Dual Catalysis
作者:Yan-Lin Li、Shi-Qi Zhang、Jie Chen、Ji-Bao Xia
DOI:10.1021/jacs.1c03527
日期:2021.5.19
A Co-catalyzed highly regio- and enantioselective reductive coupling of alkynes and aldehydes has been developed under visible light photoredox dual catalysis. A variety of enantioenriched allylic alcohols have been obtained by using unsymmetrical internal alkynes and commercially available catalyst, chiral ligand, and reagents. It is noteworthy that this approach has considerable advantages, such
在可见光光氧化还原双催化下开发了一种共催化的炔烃和醛的高度区域选择性和对映选择性还原偶联。通过使用不对称内部炔烃和市售催化剂、手性配体和试剂,已经获得了多种对映体富集的烯丙醇。值得注意的是,这种方法具有相当大的优势,例如出色的区域-(> 40 个示例> 95:5)、立体-(高达> 95:5 E / Z)和对映选择性(92-99% ee,> 35个例子)控制,反应条件温和,底物范围广,官能团相容性好,使其对映选择性炔-醛还原偶联反应有了很大的改进。
Synthesis of substituted α-methylene-γ-butyrolactones from chloroformates via palladium catalysed cyclisation–anion capture
作者:Ronald Grigg、Vladimir Savic
DOI:10.1039/b006842j
日期:——
Cyclisation of chloroformates onto proximate alkyne
functionality in the presence of a Pd(0) catalyst followed by
anion capture affords α-methylene-γ-butyrolactone derivatives
in moderate to good yields.
Terminal acetylenes are amongst the most problematic substrates for alkynemetathesis because they tend to undergo rapid polymerization on contact with a metal alkylidyne. The molybdenum complex 3 endowed with triphenylsilanolate ligands, however, is capable of inducing surprisingly effective cross‐metathesis reactions of terminal alkyl acetylenes with propynyl(trimethyl)silane to give products of
Regioselective Rhodium-Catalyzed Addition of β-Keto Esters, β-Keto Amides, and 1,3-Diketones to Internal Alkynes
作者:Thorsten M. Beck、Bernhard Breit
DOI:10.1002/ejoc.201601230
日期:2016.12
The first rhodium-catalyzed regioselective addition of 1,3-dicarbonyl compounds, including β-keto esters, β-keto amides, and 1,3-diketones, to internal alkynes furnishes branched allylic compounds. By applying RhI/DPEphos/TFA as the catalytic system, aliphatic as well as aromatic internal methyl-substituted alkynes act as suitable substrates to yield valuable branched α-allylated 1,3-dicarbonyl compounds