Synthesis of Branched Amino Polyols and Amino Hydroxy Acids

The main aim of this work is the development of synthetic routes towards amino alcohols as well as branched ¿¿ and ¿¿amino acids starting from achiral and chiral (racemic and optically active) isoxazolines and N-methylisoxazolinium salts. The isoxazolines were treated with a variety of Grignard reagents and organolithium complexes as C-nucleophiles. These results were comparable to the findings of analog additions to the ¿¿activated¿¿ isoxazolines, that is, to the isoxazolinium salts. The latter react smoothly with Grignard reagents, as well as with weaker C-nucleophiles such as sodium diethyl malonate or lithium ester enolate. At the same time it was observed, that the addition proceeds with -particly- good diastereoselectivity under mild reaction conditions, leading to good yields of the corresponding substituted isoxazolidines.