Tsuji-Trost reaction soft carbon nucleophile reactions

The water soluble vitamin (+)-biotin was synthesized by M. Seki and co-workers from L-cysteine in only 11 steps using inexpensive reagents and mild reaction conditions." The key ring forming step was an intramolecular allylic amination Tsuji-Trost reaction using a nitrogen nucleophile) of a cis allylic carbonate. As expected with a soft nucleophile, the allylation took place with an overall retention of configuration. 

The catalytic version of allylation of nucleophiles via 7r-allylpaUadium intermediates was discovered in 1970 using allylic esters and aUyl phenyl ethers as substrates (Scheme Formation of 7r-allylpaUadium complexes by oxidative addition of various allylic compounds to Pd(0) and subsequent reaction of electrophilic rr-allylpalladium complexes with soft carbon nucleophiles are the basis of the catalytic allylation. After the reaction, Pd(0) is regenerated, which undergoes oxidative addition to the allylic compounds again, making the whole reaction catalytic. The efficient catalytic cycle is ascribed to the characteristic feature that Pd(0) is more stable than Pd(II). Allylation of carbon nucleophiles with allyhc compounds via TT-allylpalladium complexes is called the Tsuji-Trost reaction. The reaction has wide synthetic applications, particularly for cyclization. " ... 

---