Application of the molybdenum catalysed hydrostannation towards propargylic esters of amino acids allows for the regioselective synthesis of α-stannylated allylic esters, suitable substrates for chelate Claisen rearrangements. α-Stannylated allylic carbonates can be subjected to palladium catalysed allylic alkylations using chelated amino acid ester enolates as nucleophiles. The stannylated amino acids obtained can be further modified via cross-coupling reactions.
Hydrostannations of propargylic glycine esters with the new hydrostannation catalyst [Mo(CO)3(CNtBu)3] (MoBI3) gave rise to alpha-stannylated allylicesters in good yield and with high regioselectivity. The chelate Claisen rearrangements of these esters allow the syntheses of gamma,delta-unsaturated amino acids with a vinylstannane moiety in the side chain. The amino acids obtained can be further modified