Synthesis of Sparsomycin via Regioselective Oxidation of Disulfide Intermediate Employing Titanium–Mandelate Complex

Dedicated to Prof. Takayuki Shioiri on the occasion of his 88th birthday

Abstract

The total synthesis of sparsomycin, a natural bioactive compound with both antitumor and antibiotic activities, was achieved using a titanium–mandelate complex that regioselectively oxidizes one of the sulfide moieties in a synthetic intermediate containing a disulfide structure. This oxidation process exhibited a regioselectivity of 73:27, preferentially oxidizing the sterically hindered sulfur atom at the desired internal position. Using the single diastereomer of the purified monosulfoxide, the synthesis of sparsomycin was then accomplished.

Key words

sparsomycin - disulfide - oxidation - titanium - mandelic acid - complex

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