64(P1-12) キラルなトリフレート誘導体を用いる光学活性天然物の合成(ポスター発表の部)  [in Japanese] 64(P1-12) SYNTHESES OF OPTICALLY ACTIVE NATURAL PRODUCTS VIA C-C BOND FORMATION OF TRIFLATES  [in Japanese]

Recently, we have developed a new and efficient method for the carbon-carbon bond forming reaction by using copper(I)-catalyzed Grignard reagents with triflates, which bear a β-oxygen fuctionality. Since those starting triflates are readily accessible from simple chiral building blocks, the procedure provides a very convenient approach to synthesize a variety of natural products in optically active forms. As an application of this methodology, we have accomplished the enantioselective syntheses of (+)-exo-brevicomin (7), one of the aggregation pheromones of bark beetles, and (5R,6S)-(-)-6-acetoxy-5-hexadecanolide (16), a major oviposition attractant pheromone of the mosquito Culex pipiens fatigans, via tosyl-triflate 6 as a common key intermediate. In both examples the use of 6 has enabled us to realize the sequential C-C bond formation in one-pot operation and hence the overall yields were considerably improved. The similar strategy could be applied to the synthesis of naturally occurring hydroxy-γ-lactone 12 (termed L-factor). As an alternative pathway, the stepwise methods towards these target molecules were also examined.