Synthesis of α-CF3 carbonylcompounds has been recognized to be difficult up to now because the polarization of CF3δ−-Iδ+ is opposite to that of CH3δ+-Iδ−, and this makes it difficult to introduce CF3+ unit to enolates. We recently reported an effective α-trifluoromethylation of ketones by using Et2Zn with Rh catalyst, but the mechanism has not fully been cleared. Now, we carried out the detailed mechanistic
Preparation of Trifluoromethylated Dihydrocoumarins, Indanones, and Arylpropanoic Acids by Tandem Superacidic Activation of 2-(Trifluoromethyl)acrylic Acid with Arenes
作者:G. K. Surya Prakash、Farzaneh Paknia、Habiba Vaghoo、Golam Rasul、Thomas Mathew、George A. Olah
DOI:10.1021/jo9026275
日期:2010.4.2
Indanones and coumarins are important intermediates for the convenient synthesis of many pharmaceutical and biologically active compounds. Fluoroorganics play a vital role in the design of very effective therapeutics due to significant enhancement in their lipophilicity, bioavailability, and fast uptake by the presence of fluorine in these molecules. Herein, we report an efficient one-pot synthesis of trifluoromethylated arylpropanoic acids, indanones, and dihydrocoumarins using Friedel-Crafts alkylation or tandem Friedel-Crafts alkylation-cycloacylation of arenes/phenols with 2-(trifluoromethyl)acrylic acid under superacidic conditions using trifluoromethanesulfonic acid. The results have been rationalized by the structure energy calculations of the involved reaction intermediates using ab initio theoretical methods.