Synthesis of Optically Active β,γ-Unsaturated α-Amino Acids and of α,β-Unsaturated γ-Amino Acids. SN2- vs. SN2’-Dichotomy of the Mitsunobu Amination of Allylic Alcohols
The first totalsynthesis of the potent antibiotic disciformycin B (2) is described, which is exceptionally isomerization‐prone and transforms into disciformycin A (1) even under notably mild conditions. To outweigh this bias, the approach to 2 hinged on the use of a silyl residue at C4 to lock the critical double bond in place and hence insure the integrity of the synthetic intermediates en route