Chemical investigation of L. tongolensis afforded two new eremophilenolides, which were identified as 3β-（2＇-methylbutanoyloxy）-8βH-eremophil-7（11）-en-12, 8α（14, 6α）-diolide （1）and 8βH-eremophil-3, 7（11）-dien-12, 8α （14, 6α）-diolide （2）. Their structures were established by spectroscopic methods including 2D NMR experiments.
This paper described a concise construction of （-）-EGCG （1f） （with an overall yield of 20% for seven steps based on the starting cinnamyl alcohol derivative 3）, featuring asymmetric dihydroxylation （ADH）, intra- and inter-molecular Mitsunobu reaction as key steps. Our strategy disclosed herein constitutes a new effective general synthetic approach toward the analogues of （-）-EGCG （1f）.
Alkyne and alkynyl species bearing a C = C functional group belong to a class of surface species which may play a pivotal role in various catalytic reaction such as CO hydrogenation, and the coordination chemistry of the corresponding ligands has been studied extensively. The interaction of alkynyl compounds with dinuclear species leading to adducts with a tetrahedral C2M2core has been recognized as one of the classical reactions in the field of organometallic chemistry.……
A convergent strategy to the key allylic silyl ether precursor 4 in our synthetic efforts toward morphinan alkaloid is presented. The vital step is the selective 1,2-addition of the organocerium agent of 6 to ketene 5.
Zhen Lei SONG Yong Qiang TU Shuan Hu GAO Yi Jun JIANG Shu Yu ZHANG
The chemical investigation of Ixeris polycephala afforded two new norsesquiterpenes, named as ixerols A and B （1-2）. Their structures were established based on spectroscopic methods including 2D NMR experiments. The absolute structure of ixerol B was determined by its CD spectrum.
Oxidative addition of carbon-centred radicals to alkenes mediated by metal salts ( MnⅢ, CeⅣ, HgⅡ,PdⅣ, AgⅠ,and CuⅡ) has received considerable attention over last decade in organic synthesis for construction of carbon-carbon bond. [1,2] Among them, manganese(Ⅲ) acetate and ceric(Ⅳ) ammonium nitrate (CAN) have been use most efficiently. Recently, CAN-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to alkenes, conjugated compounds, enol silyl ethers and alkynes, has been studied extensively. We exploited that the CAN-mediated oxidative cycloaddition of 1,3-dicarbonyl compounds to β-aryl-α,β-unsaturated ketones afforded dihydrofuran derivatives in moderate yields. All the products were characterized by 1H NMR, 13C NMR, MS and HRMS spectra.……
