Structure, Synthesis, and Chemical Reactions of Fluorinated Cyclopropanes and Cyclopropenes

Abstract

Organic chemistry

Synthesis of gem‐Difluorinated Cyclopropanes and Cyclopropenes: Trifluoromethyltrimethylsilane as a Difluorocarbene Source

“…[3] Besides biological and polymeric applications, difluorocyclopropanes are synthetically useful substrates for a variety of reactions such as thermal rearrangements, bimolecular reactions, carbocation, carbanion, and radical chemistry. [4] The synthesis of difluorocyclopropanes and difluorocyclopropenes can be achieved in various ways. However, a [2+1] cycloaddition reaction of difluorocarbene to an alkene or an alkyne has proven to be the most efficient method to date.…”

“…However, a [2+1] cycloaddition reaction of difluorocarbene to an alkene or an alkyne has proven to be the most efficient method to date. [4,5] This result has led to considerable efforts in developing reagents that can act as a source of difluorocarbene. Owing to the interaction of the lone pairs of electrons on the fluorine substituents with the carbene center, difluorocarbene is a relatively stabilized carbene species (with a singlet ground state) and is therefore less reactive than other dihalocarbenes.…”

Umpolung of Fluoroform by CF Bond Activation: Direct Difluoromethylation of Lithium Enolates

“…The formation of difluorocyclopropane and the a-deuteriodifluoromethyl product was not observed from the generation of difluoromethylene (difluorocarbene) [18][19][20] in the presence of electronrich olefins and upon quench with D 2 O, respectively.…”

Rhodium‐Catalyzed Asymmetric Intramolecular Cyclopropanation of Substituted Allylic Cyanodiazoacetates

“…Although halocyclopropanes are very useful synthons in organic synthesis, [9] there are only few reports of intramolecular cyclopropanation of allylic diazoacetates bearing halogens. [10] Therefore, a series of 3-halo-substituted allylic cyanodiazoacetates was synthesized and tested in the intramolecular cyclopropanation reaction.…”