Selective Ring-Opening of N-Alkyl Pyrrolidines with Chloroformates to 4-Chlorobutyl Carbamates.

Our study shows that among aza-heterocycles of various ring sizes, including aziridines, azetidines, pyrrolidines, and piperidines, only N-alkyl pyrrolidines undergo competitive reaction pathways with chloroformates to yield N-dealkylated pyrrolidines and 4-chlorobutyl carbamates. The pathway taken depends on the substituent on the nitrogen, i.e., ring-opening with methyl and ethyl substituents and dealkylation with a benzyl substituent. Computational calculations support the substituent-dependent product formation by showing the energy difference between the transition states of both reaction pathways. Selective ring-opening reactions of N-methyl and N-ethyl pyrrolidine derivatives with chloroformates were utilized to prepare various 4-chlorobutyl carbamate derivatives as valuable 1,4-bifunctional compounds.

Chemoselective Hydrodehalogenation of Organic Halides Utilizing Two-Dimensional Anionic Electrons of Inorganic Electride [Ca2N]+·e.

Halogenated organic compounds are important anthropogenic chemicals widely used in chemical industry, biology, and pharmacology; however, the persistence and inertness of organic halides cause human health problems and considerable environmental pollution. Thus, the elimination or replacement of halogen atoms with organic halides has been considered a central task in synthetic chemistry. In dehalogenation reactions, the consecutive single-electron transfer from reducing agents generates the radical and corresponding carbanion and thus removes the halogen atom as the leaving group. Herein, we report a new strategy for an efficient chemoselective hydrodehalogenation through the formation of stable carbanion intermediates, which are simply achieved by using highly mobile two-dimensional electrons of inorganic electride [Ca2N]+·e- with effective electron transfer ability. The consecutive single-electron transfer from inorganic electride [Ca2N]+·e- stabilized free carbanions, which is a key step in achieving the selective reaction. Furthermore, a determinant more important than leaving group ability is the stability control of free carbanions according to the s character determined by the backbone structure. We anticipate that this approach may provide new insight into selective chemical formation, including hydrodehalogenation.

Visible-Light-Induced Arylthiofluoroalkylations of Unactivated Heteroaromatics and Alkenes.

Visible-light-induced arylthiofluoroalkylations of unactivated heteroaromatics and alkenes have been developed utilizing readily available arylthiofluoroalkyl sources. This method enables simultaneous installation of sulfur and fluoroalkyl moieties, two important functional groups, which demonstrates its potential use for late-stage modifications in the synthesis of functional molecules. This method can be easily utilized to fine-tune the properties of lead molecules in drug development by controlling the number of fluorine atoms in the reagents.

Selective difluoroalkylation of alkenes by using visible light photoredox catalysis.

A visible light-induced process for selective difluoroalkylation of unactivated alkenes has been developed. The choice of base is crucial for governing the chemoselectivity of the process to produce difluoroalkylated alkanes and alkenes.