نتایج جستجو برای: favorskii

تعداد نتایج: 31  

2014
Sanjeewa N Senadheera Abraham L Yousef Richard S Givens

We have developed a new photoremovable protecting group for caging phosphates in the near UV. Diethyl 2-(4-hydroxy-1-naphthyl)-2-oxoethyl phosphate (14a) quantitatively releases diethyl phosphate upon irradiation in aq MeOH or aq MeCN at 350 nm, with quantum efficiencies ranging from 0.021 to 0.067 depending on the solvent composition. The deprotection reactions originate from the triplet excit...

2014
E. M. Kithsiri Wijeratne Patricia Espinosa-Artiles Raphael Gruener A. A. Leslie Gunatilaka

Four new nor-spiro-azaphilones, thielavialides A-D (1- 4), a new bis-spiro-azaphilone, thielavialide E (5), together with pestafolide A (6), were isolated from the endophytic fungal strain, Thielavia sp. PA0001, occurring in the healthy leaf tissue of aeroponically grown Physalis alkekengi. The structures and relative configurations of 1-5 were established on the basis of their MS and NMR data....

2013
Mark N. Vander Wal Andrew K. Dilger David W. C. MacMillan

Oxy-allyl cations have been known as transient electrophilic species since they were first proposed as intermediates in the Favorskii rearrangement in 1894. Since that time, they also have been used as a mode of activation for [4 + 3] cycloadditions in a variety of natural product syntheses. In this manuscript, we describe a method for the interception of oxy-allyl cations with a diverse range ...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1994
sasanin karimi k. grohamann l. todaro

results of the bromination and dehydrobromination of several angular methylated decalindiones are described. the key reaction, base-induced cyclization of the monobromo keto ester (3), and the dibromo ketone (4), leads to the formation of tricyclic systems (6) and (9) respectively.

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