90721-90-7Relevant academic research and scientific papers
Ring opening of methylenecyclopropanes with halides in liquid sulfur dioxide
Le?kovskis, Kristaps,Gulbe, Krista,Mishnev, Anatoly,Turks, Māris
supporting information, (2020/10/19)
Methylenecyclopropanes (MCP) undergo ring opening reactions with group I and II metal halides and ammonium halides in liquid SO2 to afford homoallylic halides, which are versatile reagents in organic synthesis. The developed reaction conditions are compatible with acid-labile substrates such as N-Boc-protected compounds. Liquid SO2 is a polar reaction medium with Lewis acid properties that solubilizes inorganic salts. The unique properties of SO2 were demonstrated by control experiments: 1) upon performing the reactions with the aforementioned salts in conventional solvents, the MCP ring opening was not observed either in the presence of catalytic amounts of H3PO4 (similar pKa to that of H2SO3), or in the absence of H3PO4; 2) a solution of SO2 in THF exhibited similar properties to that of liquid SO2.
A Stereoselective Synthesis of (+/-)-trans-Cycloalkanopiperidines and Cycloalkanopyrrolidines via Hydroboration
Brown, Herbert C.,Salunkhe, Ashok M.
, p. 1265 - 1268 (2007/10/02)
A highly stereoselective synthesis of trans-cycloalkanopiperidines and cycloalkanopyrrolidines has been achieved via hydroboration of bromocycloalkenes with dichloroboranes.The intermediate bromocycloalkylboronic acids were converted into azidocycloalkylboronates.Addition of two equivalents of boron trichloride in dichloromethane generated dichloroboranes which, by an intramolecular cyclisation gave intermediates 11.These can be readily hydrolyzed to get the corresponding important nitrogen heterocycles in good yields and excellent stereochemical purities.
