Efficient synthesis of 3-sulfolenes from allylic alcohols and 1,3-dienes enabled by sodium metabisulfite as a sulfur dioxide equivalent
作者:Hang T. Dang、Vu T. Nguyen、Viet D. Nguyen、Hadi D. Arman、Oleg V. Larionov
DOI:10.1039/c8ob00745d
日期:——
We present herein an efficient and practical method for a gram scale synthesis of 3-sulfolenes using sodium metabisulfite as a safe, inexpensive, and easy to handle sulfur dioxide equivalent. Diversely-substituted 3-sulfolenes can be prepared by reacting a variety of 1,3-dienes or allylicalcohols with sodium metabisulfite in aqueous hexafluoroisopropanol (HFIP) or in aqueous methanol in the presence
Engineering Rieske Non‐Heme Iron Oxygenases for the Asymmetric Dihydroxylation of Alkenes
作者:Christine Gally、Bettina M. Nestl、Bernhard Hauer
DOI:10.1002/anie.201506527
日期:2015.10.26
The asymmetricdihydroxylation of olefins is of special interest due to the facile transformation of the chiral diol products into valuable derivatives. Rieskenon‐hemeironoxygenases (ROs) represent promising biocatalysts for this reaction as they can be engineered to efficiently catalyze the selective mono‐ and dihydroxylation of various olefins. The introduction of a single point mutation improved
Total synthesis of hippospongic acid A, an inhibitor of gastrulation of starfish embryos, has been studied. A compound having the structure assigned to hippospongic acid A was synthesized enantioselectively. The spectral data of the synthetic compound were slightly different from those of the natural product and an alternative structure was proposed for the natural product.
对海星胚胎原肠胚形成抑制剂海马酸 A 的全合成进行了研究。对映选择性地合成了具有指定为海马酸A的结构的化合物。合成化合物的光谱数据与天然产物的光谱数据略有不同,并为天然产物提出了替代结构。
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.
作者:Timothy J. Donohoe、Paul C. M. Winship、Daryl S. Walter
DOI:10.1021/jo901243y
日期:2009.8.21
Replacing trifluoroacetic acid with it catalytic amount of Lewis acid in the osmium mediated oxidative cyclization results in higher yielding reactions that can proceed nearly an order of magnitude faster. The osmium loading can also be reduced to as little its 0.2 mol %. Furthermore, these mildly acidic conditions are capable of tolerating a wide range of acid sensitive protecting groups that are incompatible with previous cyclization conditions.