Details

Autor(en) / Beteiligte

• Ren, Jing
• Du, Feng‐Huan
• Jia, Meng‐Cheng
• Hu, Ze‐Nan
• Chen, Ze
• Zhang, Chi

Titel

Ring Expansion Fluorination of Unactivated Cyclopropanes Mediated by a New Monofluoroiodane(III) Reagent

Ist Teil von

• Angewandte Chemie International Edition, 2021-11, Vol.60 (45), p.24171-24178

Auflage

International ed. in English

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Herein, we report a new strategy for carbon−carbon bond scission and intramolecular ring expansion fluorination of unactivated cyclopropanes, which was accomplished with a new hypervalent fluoroiodane(III) reagent 1. This novel method delivers medicinally relevant 4‐fully substituted fluoropiperidines in moderate to high yields with excellent regio‐ and diastereoselectivity. Reagent 1, which has an N‐acetylbenziodazole framework, was readily synthesized via three steps in 76 % overall yield and was characterized by NMR spectroscopy and X‐ray crystallography. Owing to the presence of a secondary I⋅⋅⋅O bonding interaction between the λ3‐iodane atom and the carbonyl oxygen of the acetyl group of the N‐acetylbenziodazole framework, 1 has excellent stability and can be stored at ambient temperature for 6 months without any detectable decomposition. Density functional theory calculations and experimental studies showed that the reaction proceeds via a carbocation intermediate that readily combines with a fluoride ion to generate the product. A new strategy for C−C bond cleavage and intramolecular ring expansion fluorination of unactivated cyclopropanes has been developed. The reaction consists of C−C bond scission and ring expansion fluorination, which are both promoted by a novel hypervalent fluoroiodane(III) reagent 1.