69563-35-5Relevant academic research and scientific papers
Stereoselective Functionalization of Racemic Cyclopropylzinc Reagents via Enantiodivergent Relay Coupling
An, Lun,Tong, Fei-Fei,Zhang, Shu,Zhang, Xingang
, p. 11884 - 11892 (2020)
Efficient construction of optically pure molecules from readily available starting materials in a simple manner is an ongoing goal in asymmetric synthesis. As a straightforward route, transition-metal-catalyzed enantioconvergent coupling between widely available secondary alkyl electrophiles and organometallic nucleophiles has emerged as a powerful strategy to construct chiral center(s). However, the scope of racemic secondary alkylmetallic nucleophiles for this coupling remains limited in specific substrates because of the difficulties in stereoselective formation of the key alkylmetal intermediates. Here, we report an enantiodivergent strategy to efficiently achieve an array of synthetically useful chiral cyclopropanes, including chiral fluoroalkylated cyclopropanes and enantiomerically enriched cyclopropanes with chiral side chains, from racemic cyclopropylzinc reagents. This strategy relies on a one-pot, two-step enantiodivergent relay coupling process of the racemic cis-cyclopropylzinc reagents with two different electrophiles, which involves kinetic resolution of racemic cis-cyclopropylzinc reagents through a nickel-catalyzed enantioselective coupling with alkyl electrophiles, followed by a stereospecific relay coupling of the remaining enantiomeric cyclopropylzinc reagent with various electrophiles, to produce two types of functionalized chiral cyclopropanes with opposite configurations on the cyclopropane ring. These chiral cyclopropanes are versatile synthons for diverse transformations, rendering this strategy effective for obtaining structurally diversified molecules of medicinal interest.
SRN1 Reactions of Halocyclopropanes with Benzenethiolate Ion
Meijs, Gordon F.
, p. 606 - 611 (2007/10/02)
Ultraviolet irradiation of gem-dibromocyclopropanes 1 with benzenethiolate ion in liquid ammonia or in Me2SO solutions gave dithioacetals 2 and, in some cases, cyclopropyl phenyl sulfides 3.The reactions did not proceed in the dark and they were inhibited by m-dinitrobenzene, di-tert-butyl nitroxide, and oxygen.The bromocyclopropane 6a underwent a similar, but slower, reaction.Treatment of the bromochlorocyclopropane 7b led to replacement of only the bromine, while the dichlorocyclopropane 9b was inert under the reaction conditions.The results appear consistent with a radical chain mechanism.
