Labelling of aromatic amino-acids stereoselectively with tritium in the β-methylene group: the stereochemistry of hydroxylation in the biosynthesis of haemanthamine
Abstract
Catalytic hydrogenation of acylaminocinnamic acids proceeds cis with high stereoselectivity and provides a route to aromatic amino-acids labelled stereoselectively with deuterium or tritium in the β-methylene groups; [βR-3H]- and [βS-3H]-tyrosine, prepared in this way, were used to show that a hydroxylation step in the biosynthesis of haemanthamine proceeded with retention of configuration.