Asymmetric synthesis of (2-carbamoyloxy-1-alkenyl)cyclopropanes by intramolecular cycloalkylation

Add time:07/11/2019    Source:sciencedirect.com

Enantioenriched, diastereomerically pure (2-carbamoyloxy-1-alkenyl)cyclopropanes 22 are easily prepared via deprotonation of different allyl carbamates with n-butyllithium and (−)-sparteine (4). The mechanism of the cyclization reaction was determined and several substituted (S)-configured vinylcyclopropanes 32 were synthesized by two different methods. The configurational stability of the intermediate lithiated allyl carbamates and the half-time of epimerization were investigated in a series of silylation experiments, achieving up to 90% ee in the kinetically controlled enantiotopos-differentiating deprotonation.

We also recommend Trading Suppliers and Manufacturers of 3-(carbamoyloxy)-N,N,N,4-tetramethylanilinium iodide (cas 64050-05-1). Pls Click Website Link as below: cas 64050-05-1 suppliers

Prev:Determination of spirocyclic tetronic/tetramic acid derivatives and neonicotinoid insecticides in fruits and vegetables by liquid chromatography and mass spectrometry after dispersive liquid–liquid microextraction
Next:Luminescent europium(III) and terbium(III) ions encapsulated in a 2-aminoethoxy or carbamoyloxy substituted calixarene host)