摘要:
Chiral aminals are prepared from chiral C2 symmetrical diamines and aldehydes. The chiral imidazolidine ring exerts its stereocontrol either through steric or chelation effects. Reaction of aqueous glyoxal with diamine 1 results in a new chiral synthon 6;this ''chiron'' is a useful precursor for alpha-hydroxy aldehydes and for alpha-amino aldehydes. An aminal of nicotinaldehyde 7 reacts stereoselectively with organocopper reagents to afford a chiral dihydropyridine, which is a starting point for several shea asymmetric syntheses of indolo- and benzo-quinolizine alkaloids.
摘要:
Ager et al discuss the use of completely reduced derivatives, alpha-amino alcohols, as chiral auxiliaries. A number of ligand systems have been derived from 1,2-amino alcohols.