Brad Sleebs - Diastereoselective synthesis highly functionalised β2,2,3-amino acids from 4-substituted-1,3-oxazinan-6-ones

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      Publication Details (including relevant citation   information):

      Tetrahedron  (2012),   68(24),   4745-4756.


      1,3-Oxazinan-6-ones were used to generate substituted   β2,2,3-substituted amino acid derivatives. The   enolates of 1,3-oxazinan-6-ones were trans-selectively   intercepted with electrophiles. This alkylation was subsequently   optimized for a one-pot dialkylation to form 5,5-disubstituted   oxazinanones. The initial 5-monomethylated compounds could be   enolized and then diastereoselectively intercepted with different   electrophiles to form differentially 5,5-disubstituted products.   The 5,5-dialkylated oxazinanones were then transformed to   N-methyl β2,2,3-substituted amino acids by   reductive cleavage. Hydrolysis or solvolysis of the oxazinanones   afforded β2,2,3-substituted amino acids or esters,   respectively. The chemistry thus provides access to a range of   symmetrical and stereopure β2,2,3-substituted amino   acids and further establishes 1,3-oxazinan-6-ones as useful   intermediates.

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