通过气相色谱分析随后分离的阿魏木霉菌株11的发酵肉汤,然后使用Finnigan MAT GCQ仪器进行质谱检测。在C18和硅胶柱中进行预分离后,分别获得十九个吡喃酮和二氧戊环衍生物以及两种脂族酯。其中,四种二氧戊环衍生物先前尚未鉴定。发现主要成分为5,5'-二甲基-2H-吡喃-2-on。用于确定保留时间和峰面积(以离子数测量)的相对标准偏差分别为0.1%和4.5%。
Electronically Mismatched Cycloaddition Reactions via First-Row Transition Metal, Iron(III)–Polypyridyl Complex
作者:Jung Ha Shin、Eun Young Seong、Hyeon Jin Mun、Yu Jeong Jang、Eun Joo Kang
DOI:10.1021/acs.orglett.8b02541
日期:2018.9.21
one-electron oxidant, producing radicalcations from olefins and promoting the efficient radicalcation [2 + 2] and [2 + 4] cycloaddition reactions. Subsequent chain propagation afforded trisubstituted cyclobutane or cyclohexene derivatives, and this facile route enables the replacement of rare metals with sustainable, green, and inexpensive iron in radicalcationcycloadditions.
Photooxidizing Chromium Catalysts for Promoting Radical Cation Cycloadditions
作者:Susan M. Stevenson、Matthew P. Shores、Eric M. Ferreira
DOI:10.1002/anie.201501220
日期:2015.5.26
The photooxidizing capabilities of selected CrIII complexes for promotingradicalcationcycloadditions are described. These complexes have sufficiently long‐lived excited states to oxidize electron‐rich alkenes, thereby initiating [4+2] processes. These metal species augment the spectrum of catalysts explored in photoredox systems, as they feature unique properties that can result in differential
Radical Cation Cyclopropanations via Chromium Photooxidative Catalysis
作者:Francisco J. Sarabia、Eric M. Ferreira
DOI:10.1021/acs.orglett.7b01095
日期:2017.6.2
The chromium photocatalyzed cyclopropanation of diazo reagents with electron-rich alkenes is described. The transformation occurs under mild conditions and features specific distinctions from traditional diazo-based cyclopropanations (e.g., avoiding β-hydride elimination, chemoselectivity considerations, etc.). The reaction appears to work most effectively using chromium catalysis, and a number of
A highly efficient and selective rearrangement reaction of bromohydrins to aldehydes mediated by CF3CO2ZnEt was described. The secondary and tertiary aldehydes were prepared under mild conditions in good to excellent yields (85–99%). The scope and limitations of this rearrangement process were also investigated.
描述了由CF 3 CO 2 ZnEt介导的溴代醇对醛类的高效选择性重排反应。仲醛和叔醛是在温和的条件下以良好至极佳的收率(85–99%)制备的。还研究了这种重排过程的范围和局限性。
Et<sub>2</sub>Zn-Mediated Rearrangement of Bromohydrins
作者:Lezhen Li、Peijie Cai、Qingxiang Guo、Song Xue
DOI:10.1021/jo800231s
日期:2008.5.1
and highly efficient method for the rearrangement of bromohydrins mediated by Et2Zn to synthesize carbonylcompounds was described. Various β-bromo alcohols were treated with 0.6 equiv of Et2Zn to form a zinc complex in CH2Cl2 at room temperature for 2 h, followed by 1,2-migration to give the corresponding carbonylcompounds. This remarkable and clean rearrangement is general for acyclic and cyclic bromohydrins