Catalytic asymmetric aminolactonization

What is it about?

Catalytic and enantioselective aminolactonization of alkenoic acid esters via in situ aziridination has been developed using chiral BOX-Cu(OTf)2 catalyst and silica-gel to provide exclusively trans-gama- and delta-lactones including additional all-carbon quaternary stereo-centre with up to 98% ee in good to excellent yields. This method also provides an efficient route to non-racemic N-Boc-beta-benzyl-beta-amino acids.

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Why is it important?

Oxidative intramolecular remote functionalization of alkenes is an efficient tool for the construction of lactones. Halolactonization have proven to be versatile transformation in organic synthesis. It needs additional steps transforming to amino group and often elimination is major hitches. Direct transformation of alkenoic acids to corresponding amino –lactones could be more advantageous. There is no suitable asymmetric method for the conversion of alkenoic acid/ester to the amino-lactone.