Practical Synthesis of (±)-Nyasol

A practical total synthesis of racemic nyasol (7) was explored. The α-hydroxyketo compound 3 was prepared from commercially available starting materials in two steps. Chelation-controlled reduction of the α-hydroxyketo compound 3 with Zn(BH₄)₂ gave the anti-1,2-diol compound 4 as the major product (anti/syn = 11.5:1). Stereospecific elimination reaction of a 1,3-cyclic thionocarbonate intermediate (5) exclusively yielded the Z-alkene compound 6. Our total synthesis is very concise (seven steps), uses commercially available starting materials, and offers good overall yield (40%).