- A scalable and green one-minute synthesis of substituted phenols
-
A mild, green and highly efficient protocol was developed for the synthesis of substituted phenols via ipso-hydroxylation of arylboronic acids in ethanol. The method utilizes the combination of aqueous hydrogen peroxide as the oxidant and H2O2/HBr as the reagent under unprecedentedly simple and convenient conditions. A wide range of arylboronic acids were smoothly transformed into substituted phenols in very good to excellent yields without chromatographic purification. The reaction is scalable up to at least 5 grams at room temperature with one-minute reaction time and can be combined in a one-pot sequence with bromination and Pd-catalyzed cross-coupling to generate more diverse, highly substituted phenols.
- Elumalai, Vijayaragavan,Hansen, J?rn H.
-
p. 40582 - 40587
(2020/11/18)
-
- Method for photocatalytic synthesis of polybrominated phenol compound in water phase
-
The invention discloses a method for photocatalytic synthesis of a polybrominated phenol compound in a water phase, comprising the following steps: adding a catalytic amount of a radical initiator, aphenol derivative and low-toxic and cheap bromide salt and water into a reaction vessel, reacting at room temperature at 5 W power in a photocatalytic reactor for a certain period, extracting with ethyl acetate and then re-crystallizing to obtain a polybrominated phenol compound. The above radical initiator is eosin, azobisisobutanol, sodium persulfate, ammonium persulfate or potassium persulfate.The free radical initiator and the bromine salt are cheap and easily available, and the method is an ideal synthesis method of the polybrominated phenol compound. According to the method, low-toxicity bromine salt instead of liquid bromine is used to carry out a bromination reaction, unstable and explosive hydrogen peroxide is replaced with the cheap and easily-available free radical initiator, and an emerging photocatalytic method is used. The polybrominated phenol compound can be obtained in a high yield by only using a 5W power lamp for the reaction, the reaction selectivity is high, by-products are less, and the post-treatment is simple.
- -
-
Paragraph 0012; 0033
(2019/08/30)
-
- Concise total synthesis of (±)-aspidospermidine via an oxidative Hosomi-Sakurai process
-
A concise total synthesis of (±)-aspidospermidine has been achieved in twelve steps from inexpensive 4-ethylphenol, based on an oxidative Hosomi-Sakurai reaction via the concept of "aromatic ring umpolung".
- Sabot, Cyrille,Guerard, Kimiaka C.,Canesi, Sylvain
-
supporting information; experimental part
p. 2941 - 2943
(2009/12/01)
-