Single C−F Bond Activation of the CF₃ Group with a Lewis Acid: CF₃‐Cyclopropanes as Versatile 4,4‐Difluorohomoallylating Agents

Abstract

The selectivea ctivation of one CÀFb ond (single activation) of the CF 3 group on cyclopropanes was achieved for the first time. When (trifluoromethyl)cyclopropanes were treated with arenes,a llylsilanes, silyl enol ethers,o rh ydrosilanesi nt he presence of Me 2 AlCl, fluoride elimination andt he subsequent ring openingp roceeded to afford 4,4-difluorohomoallylated products.I nt he absence of external nucleophiles,a na lkyl group of AlR 3 was effectively introduced to provide the corresponding 1,1-difluoroalkenes.

Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

“…In 2018, they reported an unprecedented single C−F activation of CF 3 ‐cyclopropanes 274 promoted by Me 2 AlCl as the Lewis acid (Scheme 73). [101] Several nucleophiles, such as arenes 275 and organosilicons were treated with CF 3 ‐cyclopropane moieties to give 4,4‐difluorohomoallylated products 276 through fluoride elimination and ring‐opening processes. Afterward, the same group presented another Lewis‐acid‐promoted single C−F bond activation of CF 3 ‐cyclopropanes 280 (Scheme 74).…”

Fluoroalkyl N-sulfonyl hydrazones: An efficient reagent for the synthesis of fluoroalkylated compounds

“…Trifluoromethyl-substituted cyclopropanes are appealing synthons in medicinal chemistry because they combine the conformational rigidity of three-membered rings with fluorinated substituents' unique and highly beneficial properties [66,67]. The Ishikawa group [68] was the first to use fluoroalkyl N-sulfonyl hydrazones in cyclopropanation reactions, successfully synthesizing a series of CF 3 -substituted cyclopropanes (30) by treating styrene with CF 3 -substituted N-tosyl hydrazones (29) in the presence of tetrabutylammonium chloride, a FeCl(TPP) catalyst, and sodium methoxide. This method provides an efficient alternative to Carreira's method, which involves Fe-catalyzed trifluoromethyl cyclopropanation of styrene with trifluorodiazoe-Scheme 7 Cross-coupling of CF 3 -substituted N-tosyl hydrazones with alkyl/aryl lithium or aryl boronates (color online).…”

“…However, the cyclopropanation reaction mentioned above, which uses N-tosyl hydrazones lacks substrate and gave poor yields [68]. In this context, the Bi group [36], investigated the cyclopropanation reaction using TFHZ-Tfs as a diazo precursor.…”

Analisis Molekular dan Transpor Ion Amonium Clorida

“…Banyak senyawa yang paling penting pada bidang industry, seperti amonia (42)(43)(44)(45)(46) , asam nitrat (47) , nitrat organik (propelan dan bahan peledak), serta sianida, mengandung nitrogen. Nitrogen banyak ditemukan dalam bentuk ikatan rangkap dua dan tiga, namun ada juga yang membentuk ikatan tunggal(single bond) (48)(49)(50)(51)(52)(53) . Ikatan rangkap tiga pada atom nitrogen sangat kuat jika dibandingkan dengan ikatan tunggal dan ikatan rangkap dua.…”