Stereospecific 1,3-Aminobromination of Donor-Acceptor Cyclopropanes
Saikat Das1, Constantin G Daniliuc1, Armido Studer1
1NRW Graduate School of Chemistry, Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
Abstract:
Sn(OTf)2 -catalyzed 1,3-aminobromination of donor-acceptor cyclopropanes with various sulfonyl amides or electron-poor anilines and N-bromosuccinimide is reported. These experimentally straightforward reactions occurred with complete regio- and stereospecificity (for anilines) to give γ-aminated α-brominated malonic diesters in good to excellent yields (up to 98 %). These compounds served as valuable substrates for subsequent reactions to provide substituted azetidines and γ-lactams in high yields.
Related Concept Videos
Prochirality
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Stereoisomerism of Cyclic Compounds

![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
