78(P-75) 抗腫瘍活性シクロファン系天然物Cylindrocyclophane類の不斉全合成研究(ポスター発表の部)

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[7.7] Paracyclophanes, cylindrocyclophanes (A〜F,1-6) and nostocyclophane D (7), are a new class of macrocyclic compounds isolated from blue-green algae, Cylindrospermum licheniforme and Nostoc linckia, by Moore, et al. in 1990. These 22-membered cyclophanes exhibit potent antitumor activity. The enantioselective syntheses of cylindrocyclophane A (1) have already reported by Smith, et al. and Hoye,et al., respectively. However, the structure-activity relationship of cyclophanes is not clear. Therefore, we designed new, convergent synthetic routes to prepare cylindrocyclophane A (1) and its derivatives to address the above mentioned problems. We report herein our formal total synthesis of cylindrocyclophane A (1). Syringaldehyde (15) was transformed into triflate 16 for the three steps. (E)-Stannylalkene 18 was obtained from propargyl alcohol 17 which was synthesized from (+)-diethyl tartrate by the known procedures. By the Stille coupling reaction of (E)-Stannylalkene 18 with triflate 16 followed by the Johnson-Claisen rearrangement, ester 20 was obtained, which was constructed the chiral center at C-20 of cylindrocyclophane A (1). The ester 20 was transformed into olefin 23 for the five steps. The chiral centers at C-1 and C-2 were constructed through the Evans asymmetric aldol reaction of aldehyde 24, which was obtained from olefin 23, and oxazolidinone 25. The coupling product 26 was transformed into important intermediate 28, which was synthesized by Smith, et al. for the synthesis of cylindrocyclophane A (1). The synthesized diolefin 28 was identical with the reported 28 in all spectroscopic properties. Further studies toward the total syntheses of cylindrocyclophane A (1) and cylindrocyclophane's derivatives are now under way using catalytic olefin cross methathesis.
天然有機化合物討論会の論文
2004-10-01

78(P-75) 抗腫瘍活性シクロファン系天然物Cylindrocyclophane類の不斉全合成研究(ポスター発表の部)

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