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。
Enantio- and Diastereodivergent Construction of 1,3-Nonadjacent Stereocenters Bearing Axial and Central Chirality through Synergistic Pd/Cu Catalysis
through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetricallenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee)
Gold(I)-Catalyzed Rearrangement of Propargyl Benzyl Ethers: A Practical Method for the Generation and in Situ Transformation of Substituted Allenes
作者:Benoit Bolte、Yann Odabachian、Fabien Gagosz
DOI:10.1021/ja1020469
日期:2010.6.2
of benzyl propargyl ethers react with a gold(I) catalyst to furnish variously substituted allenes via a 1,5-hydride shift/fragmentation sequence. This transformation is rapid and practical. It can be performed under very mild conditions (room temperature or 60 degrees C) using terminal as well as substituted alkyne substrates bearing a primary, secondary, or tertiary benzyl ether group. The allenes
3‐butadienes with various substitution patterns were formed in good to high yields in a copper‐catalyzed borylation of α‐alkoxy allenes with bis(pinacolato)diboron (see scheme; Bn=benzyl, pin=pinacolate, L is an N‐heterocyclic carbene ligand). The products were found to be useful intermediates for the synthesis of cyclic vinyl boranes, α,β‐unsaturated ketones, and functionalized multisubstituted dienes.
Rhenium(I)-Catalyzed Generation of α,β-Unsaturated Carbene Complex Intermediates from Propargyl Ethers for the Preparation of Cycloheptadiene Derivatives
作者:Hideyuki Sogo、Nobuharu Iwasawa
DOI:10.1002/anie.201604371
日期:2016.8.16
The rhenium(I)‐catalyzed generation of α,β‐unsaturated carbene complex intermediates from easily available propargyl ethers was achieved for the concise construction of cycloheptadiene derivativesthrough the formal [4+3] cycloaddition reaction with siloxydienes.