Mitsutaka Tanaka

Synthesis of a key intermediate for D-biotin via 1,3-cycloaddition of a thiocarbonyl ylide and sila-Pummerer rearrangement

An efficient preparation of a d-biotin intermediate, (±)-(3aα,4α,6aα)-1,3-dibenzyl-3a,4,6,6a-tetrahydro-4-hydroxy-1H-thieno[3,4-d]imidazol-2(3H)-one was accomplished by use of 1,3-cycloaddition of a thiocarbonyl ylide, Curtius rearrangement and sila-Pummerer rearrangement. Addition of p-toluenesulfonic acid was found to be effective to promote sila-Pummerer rearrangement of sterically unfavorable anti-2-trimethylsilyl sulfoxide