220130-94-9Relevant articles and documents
Syntheses of optically active α-amino nitrites by asymmetric transformation of the second kind using a principle of O. Dimroth
Hassan, Nasser A.,Bayer, Erwin,Jochims, Johannes C.
, p. 3747 - 3757 (2007/10/03)
A mixture of solids As and Bs in equilibrium with the dissolved compounds A1 and B1 is transformed completely into one pure solid, say Bs, if the dissolved compounds A1?B1 are equilibrating in solution. This is applied to transform 1:1 mixtures of solid diastereomeric amygdalates (2-hydroxy-2-phenylacetates; mandelates) (R,R)-3 + (S,R)-3 prepared from racemic α-amino nitriles (R,S)-1 with (R)-mandelic acid 2 into stereochemically pure single diastereomers (R,R)-3, or (S,R)-3 (de > 97%) ('asymmetric transformation of the second kind by application of Dimroth's principle'). Decomposition of the amygdalates (R,R)-3, or (S,R)-3, with aqueous base affords the enantiomerically pure α-amino nitriles (A)-1, or (S)-1 (ten examples). The chiral auxiliary (R)-mandelic acid is recovered almost quantitatively. The optically active α-amino nitriles are hydrolyzed to amides 6, and further to α-N-alkylamino acids 7. N-Benzylamino acids 7 are hydrogenated to α-amino acids 8. Some of the optically active α-amino nitriles 1 are reduced to optically active 1,2-diamines 9. In most cases, absolute configurations could be assigned by comparison of the specific rotations observed with those of authentic compounds.
