Pd(0)-Catalyzed Alkene Oxy- and Aminoalkynylation with Aliphatic Bromoacetylenes
摘要:
Tetrahydrofurans and pyrrolidines are among the most important heterocycles found in bioactive compounds. Cyclization-functionalization domino reactions of alcohols or amines onto olefins,constitute one of the most efficient methods to access them. In this context oxy- and aminoalkynylation are especially important reactions because of the numerous transformations possible with the triple bond of acetylenes yet these methods have been limited to the use of silyl protected acetylenes. Herein we report the first palladium-catalyzed oxy- and aminoalkynylation using aliphatic bromoalkynes which proceeded with high diastereoselectivity and functional group tolerance. A one-pot hydrogenation of the triple bond gave then access to alkyl-substituted tetrahydrofurans and pyrroldines. Finally a detailed study of the side products formed during the reaction gave a first insight into the reaction mechanism.
One-Pot Three-Component Synthesis of Vicinal Diamines via In Situ Aminal Formation and Carboamination
作者:Ugo Orcel、Jerome Waser
DOI:10.1002/anie.201607318
日期:2016.10.4
A synthesis of vicinal diamines via in situ aminalformation and carboamination of allyl amines is reported. Employing highly electron‐poor trifluoromethyl aldimines in their stable hemiaminal form was key to enable both a fast and complete aminalformation as well as the palladium‐catalyzed carboamination step. The conditions developed allow the introduction of a wide variety of alkynyl, vinyl, aryl
Rh(II)-Catalyzed Alkynylcyclopropanation of Alkenes by Decarbenation of Alkynylcycloheptatrienes
作者:Mauro Mato、Marc Montesinos-Magraner、Arnau R. Sugranyes、Antonio M. Echavarren
DOI:10.1021/jacs.1c05422
日期:2021.7.21
(including derivatives of complex drug-like molecules), versatile intermediates that previously required much lengthier synthetic approaches. Combining experiments and DFT calculations, the complete mechanistic picture for the divergent reactivity of alkynylcycloheptatrienes under metal catalysis has been unveiled, rationalizing the unique selectivity displayed by rhodium(II) complexes.
炔基环丙烷在有机合成和药物化学方面都有着广阔的应用前景,但由于其制备过程中存在的挑战,其研究仍相当不足。我们描述了一种基于铑 (II) 催化的 7-炔基环庚三烯脱碳化的烯烃炔基环丙烷化的便捷两步方法。所采用的催化系统规避了与这些底物相关的基本问题,这些底物通常在金属催化下通过6-内环化或环收缩途径演变。这种独特的性能可以快速访问各种炔基环丙烷(包括复杂的类药物分子的衍生物)库,这是以前需要更长的合成方法的多功能中间体。结合实验和DFT计算,揭示了金属催化下炔基环庚三烯不同反应性的完整机理图,合理化了铑(II)配合物所表现出的独特选择性。
Palladium-Catalyzed Vicinal Amino Alcohols Synthesis from Allyl Amines by In Situ Tether Formation and Carboetherification
作者:Ugo Orcel、Jerome Waser
DOI:10.1002/anie.201500636
日期:2015.4.20
Vicinalaminoalcohols are important structural motifs of bioactive compounds. Reported herein is an efficient method for their synthesis based on the palladium‐catalyzed oxy‐alkynylation, oxy‐arylation, or oxy‐vinylation of allylic amines. High regio‐ and stereoselectivity were ensured through the in situformation of a hemiaminal tether using the cheap commercially available trifluoroacetaldehyde
Catalytic Enantioselective Allylations of Acetylenic Aldehydes via 2-Propanol-Mediated Reductive Coupling
作者:Gilmar A. Brito、Franco Della-Felice、Guoshun Luo、Alexander S. Burns、Ronaldo A. Pilli、Scott D. Rychnovsky、Michael J. Krische
DOI:10.1021/acs.orglett.8b01776
日期:2018.7.6
O-benzoates modified by (S)-SEGPHOS or (S)-Cl,OMe-BIPHEP catalyze enantioselective 2-propanol-mediated reductive couplings of diverse nonmetallic allyl pronucleophiles with the acetylenic aldehyde TIPSC≡CCHO. Absolute stereochemistries of the resulting secondary homoallylic–propargylic alcohols were assigned using Rychnovsky’s competing enantioselective conversion method.
( S )-SEGPHOS 或 ( S )-Cl,OMe-BIPHEP 修饰的环金属化 π-烯丙基C,O-苯甲酸酯催化多种非金属烯丙基亲核试剂与乙醛TIPSC=CCHO 的对映选择性 2-丙醇介导的还原偶联。使用 Rychnovsky 的竞争性对映选择性转化方法确定所得仲高烯丙醇-炔丙醇的绝对立体化学。