33 アレニルメチルトリメチルシランの反応性を利用する天然物合成(ポスター発表の部)

抄録

Ti(IV) chloride mediated reaction of allenylmethyltrimethylsilane (2) with various aldehydes and acetals has been examined establishing an efficient method for the preparation of racemic dienol derivatives rac-4. Application of this method to chiral acetals 6 led to chiral dienols 4 with high optical purity (≥90% ee) which were alternatively synthesized by the Sharpless kinetic resolution of rac-4. The synthetic utility of the methods described above has been demonstrated, at first, in the enantiocontrolled syntheses of branched-chain sugars, L-arcanose (24) and L-olivomycose (29) starting from Lewis acid mediated reaction of 2 with (S)-2-benzyloxy-propanol (16). Furthermore, concise enantioselective synthesis of the key synthetic intermediate 34 for anticancer anthracyclines has been accomplished starting from Lewis acid mediated reaction of 2 with the chiral acetal 35.