Rhodium(III)‐catalyzed Construction of D‐A Type Polyheteroaromatics with Fluorinated Benzothiadiazole as a Modifiable Acceptor Block

Abstract

An efficient pathway to a new family of fluorinated polyheteroaromatic D-A molecules has been developed. The method is based on the Rh(III)-catalyzed regioselective [4 + 2]-annulation of N-(pivaloyloxy)-benzamides with 4-ethynyl-5,6-difluoro-7-(p-methoxyphenyl)-2,1,3-benzothiadiazole as a key step followed by the aromatization/Suzuki coupling sequence to furnish the target D-A systems with modifiable acceptor block. The discovered difference in reactivity between ArB(OH) 2 and ArBPin allows performing a divergent modification of BTD acceptor block by the manipulation of aryl boronic reagents in the ortho-selective CÀ F activation of the fluorinated BTD moiety under Suzuki reaction conditions to furnish new D 1 -π-A-D 2 systems in good yields. Such stepby-step modification of the acceptor block has been achieved by Pd-catalyzed CÀ F bond activation under isoquinoline ring assistance for the first time.

Noble Metal versus Abundant Metal Catalysts in Fine Organic Synthesis: Cost Comparison of C–H Activation Methods

“…We decided to compare the costs of various methods involving catalytic C–H activation reactions using the example of the synthesis of a model heterocyclic compound 3,4-diphenyl-isoquinolone ( 1 ) (Scheme ). Isoquinolones like 1 are widely used as structural components of fluorescent materials − and biologically active molecules. , They are popular target products for C–H activation reactions and, therefore, are convenient for direct comparison of these methods.…”