A highly efficient protocol for the large-scale oxidative cyclization of 1,5-dienes is described. This convenient ruthenium(VIII)-catalyzed (0.2 mol%) cyclization reaction allows the preparation of cis-2,5-disubstituted tetrahydrofurans in high yields (up to 92%) and excellent diastereomeric ratio (>95:5 dr). This simple and reliable method is insensitive to moisture and air and can, therefore, be carried out in an open reaction vessel.
A Highly Efficient Procedure for Ruthenium Tetroxide Catalyzed Oxidative Cyclizations of 1,5-Dienes
作者:Stefanie Roth、Sabrina Göhler、Huan Cheng、Christian B. W. Stark
DOI:10.1002/ejoc.200500052
日期:2005.10
for the oxidative cyclization of 1,5-dienes, which generally allows for high yields and selectivities. A solid-supported terminal oxidant and a finely tuned solvent mixture have both been identified as critical factors for this high efficiency. As little as 0.2 mol-% ruthenium(III) chloride as a pre-catalyst for the rutheniumtetroxide generated in situ is required to accomplish oxidative cyclization
An Aged Precatalyst Solution Leads to High Catalytic Activity: Oxidative Cyclization of 1,5-Dienes Using ppm Amounts of Ruthenium
作者:Juliane Adrian、Stefanie Roth、Christian B. W. Stark
DOI:10.1002/cctc.201600179
日期:2016.5.9
diastereoselective preparation of THF diols from simple achiral 1,5‐diene starting materials with significant relevance to target‐oriented and natural product synthesis. We here report that an aged precatalyst solution exhibits an extraordinarily high reactivity. Thus, even at 50 ppm catalyst loading, impressive results were achieved with good to high yields and excellent diastereoselectivities for the four stereogenic
四氧化钌催化的直接氧化环化是一种强大的合成方法,可从简单的非手性1,5-二烯起始原料中非对映选择性地制备THF二醇,与目标定向和天然产物的合成具有显着的相关性。我们在这里报告老化的预催化剂溶液表现出异常高的反应性。因此,即使在催化剂负载量为50 ppm的情况下,对于在此单步转化中建立的四个立体异构中心,也获得了令人印象深刻的结果,具有良好的高收率和出色的非对映选择性。周转次数高达15000,周转频率高达3660 h -1获得了。用光谱法分析了老化效果,并给出了解释该反应性的初步假设。最后,通过使用一组具有不同取代模式和不同反应双键几何形状的底物,证明了这种效应在氧化环化化学中的普遍性。
A Double Donor-Activated Ruthenium(VII) Catalyst: Synthesis of Enantiomerically Pure THF-Diols
作者:Huan Cheng、Christian B. W. Stark
DOI:10.1002/anie.200903090
日期:2010.2.22
Enantiomerically pure tetrahydrofurans are obtained with high position‐ and stereoselectivity through a ruthenium(VII)‐catalyzedoxidative cyclization of 5,6‐dihydroxy alkenes (see scheme TPAP=tetrapropylammonium perruthenate). A dual activation modifies the reactivity and increases the carbophilicity of the transition metal so that an otherwise unusual dioxygenation with perruthenate occurs.
Asymmetric Permanganate-Promoted Oxidative Cyclization of 1,5-Dienes by Using Chiral Phase-Transfer Catalysis This work was supported by the EPSRC (J.F.K.) and the Royal Society (R.C.D.B.). We thank Dr. Barry Lygo (University of Nottingham) for helpful discussions, and Syngenta and Merck Sharp and Dohme for unrestricted grants.