Diastereofacial selectivity in intermolecular nitrone cycloadditions to chiral allyl ethers. Application to Chiral Synthesis of Coniine
作者:Masayuki Ito、Masae Maeda、Chihiro Kibayashi
DOI:10.1016/0040-4039(92)80019-g
日期:1992.6
The intermolecular cycloadditions of a cyclic nitrone to chiral allyl ethers take place with erythro selectivity, where the degree of selectivity achieved is dependent upon the size of the alkyl substituent attached to the allylic chiral center, and these reactions are applied to the synthesis of optically active alkaloid coniine.
The carboazidation of chiralallylsilanes has been investigated by varying the nature of the substituents at the silicon center and on the carbon framework. The influence of temperature and the nature of the sulfonyl azide, as well as the stereochemistry of the remote stereogenic center, on the 1,2-diastereocontrol of the process were considered. Good to excellent levels of diastereocontrol were generally
Regio- and Enantiospecific Rhodium-Catalyzed Allylic Etherification Reactions Using Copper(I) Alkoxides: Influence of the Copper Halide Salt on Selectivity
作者:P. Andrew Evans、David K. Leahy
DOI:10.1021/ja026337d
日期:2002.7.1
The transition metal-catalyzed allylic etherification represents a fundamentally important cross-coupling reaction for the construction of allylic ethers. We have developed a new regio- and enantiospecific rhodium-catalyzed allylic etherification of acyclic unsymmetrical allylic alcohol derivatives using copper(I) alkoxides derived from primary, secondary and tertiary alcohols. This study demonstrates
Totalsynthesis of the proposed structure 2 for phomopsin B was achieved by using an intramolecular olefin metathesis as a key step. The spectral data, however, did not match with those of the natural product reported. Re-examination of the reported NMR data led to the structural revision of phomopsin B to known dothiorelone A 18. The R configuration of dothiorelone A was determined by total synthesis
通过使用分子内烯烃复分解作为关键步骤,实现了针对视蛋白B的拟议结构2的全合成。然而,光谱数据与报道的天然产物的光谱数据不匹配。重新检查所报告的NMR数据导致将视蛋白B的结构修改为已知的dothiorelone A 18。Dothiorelone A的R构型是通过与手性烯烃19的交叉复分解通过全合成确定的。
Stereoselective nitrile oxide cycloadditions to chiral allyl ethers and alcohols. The inside alkoxy effect
作者:K. N. Houk、Susan R. Moses、Yun Dong Wu、Nelson G. Rondan、Volker Jager、R. Schohe、Frank R. Fronczek