Regio- and stereoselective synthesis of gem-difluorocyclopropanes using 4-bromo-4,4-difluorocrotonate
摘要:
Regio- and stereoselective formation of the functionalized gem-difluorocyclopropane derivative was achieved through the Michael addition of lithium enolate of ester or amide with 4-bromo-4,4-difluorocrotonate I followed by the triethylborane-O-2 mediated intramolecular substitution reaction.
The reaction of perfluoroalkylated α,β-unsaturated phosphorates with saturated methanolic ammonia solution afforded 2-amino-2-perfluoroalkylethylphosphonates, and with benzylamine gave 2-benzylamino-2-perfluoroalkylethylphosphonates which upon hydrogenation gave 2-amino-2-perfluoroalkylethylphosphonates.
Asymmetric Organocatalyzed Friedel–Crafts Reaction of Trihaloacetaldehydes and Phenols
作者:David Svestka、Jan Otevrel、Pavel Bobal
DOI:10.1002/adsc.202200180
日期:2022.7.5
Herein we report the asymmetric organocatalyzed method for the Friedel–Craftsreaction between activatedphenols and trihaloacetaldehydes. A three-phase screening including 41 compounds was employed to identify a catalyst structure based on 3,5-dinitrobenzamide of 9-amino-epi-cinchonidine as the lead catalytic molecule. Under the optimized reaction conditions, the above catalyst offered trihalohydroxyalkylated