Stable but reactive perfluoroalkylzinc reagents: application in ligand-free copper-catalyzed perfluoroalkylation of aryl iodides.

The aromatic perfluoroalkylation catalyzed by a copper(I) salt with bis(perfluoroalkyl)zinc reagents Zn(RF)2(DMPU)2, which were prepared and then isolated as a stable white powder from perfluoroalkyl iodide and diethylzinc, was accomplished to provide the perfluoroalkylated products in good-to-excellent yields. The advantages of this reliable and practical catalytic reaction are 1) air-stable and easy-to-handle bis(perfluoroalkyl)zinc reagents can be utilized, 2) the reagent is reactive and hence the operation without activators and ligands is simple, and 3) not only trifluoromethylation but also perfluoroalkylation can be attained.

Development of (Trifluoromethyl)zinc Reagent as Trifluoromethyl Anion and Difluorocarbene Sources.

The trifluoromethylation of carbonyl compounds is accomplished by the stable (trifluoromethyl)zinc reagent generated and then isolated from CF3I and ZnEt2, which can be utilized as a trifluoromethyl anion source (CF3(-)). The reaction proceeds smoothly with diamine as a ligand and ammonium salt as an initiator, providing the corresponding trifluoromethylated alcohol products. Moreover, the (trifluoromethyl)zinc reagent can also be employed as a difluorocarbene source (:CF2) not only for gem-difluoroolefination of carbonyl compounds with phosphine but also for gem-difluorocyclization of alkenes or alkynes via the thermal decomposition, respectively.

Investigation of Regorafenib-induced Hypothyroidism in Patients with Metastatic Colorectal Cancer.

Hypothyroidism is one of the side-effects caused by regorafenib. In the Japanese subset of the CORRECT study, hypothyroidism developed in 1.5% of the patients, but was not grade 3 or higher in any patient. Regorafenib is an oral multi-kinase inhibitor that has the same mechanism of action as sunitinb. However, the reported incidence of sunitinb-related hypothyroidism varies widely, ranging from 16.0% in clinical trials to 35.4% in post-marketing surveillance studies. In general, symptoms of hypothyroidism include fatigue and dysphonia. Hyperthyroidism must, therefore, be appropriately managed in order to maintain patient quality of life and avoid a critical level of hypothyroidism. During the first cycle of treatment with regorafenib, the incidence of abnormal thyroid-stimulating hormone (TSH) elevation was 31.4%. Our results suggest that thyroid function tests should be performed from day 1 of treatment with regorafenib. It would be prudent to consider routine monitoring of thyroid function in all patients who receive regorafenib and to recommend endocrinological consultation as necessary.