29 分子内デッツ反応を用いたケンドマイシンの全合成(口頭発表の部)

DOI

書誌事項

タイトル別名
  • Total Synthesis of Kendomycin using Intramolecular Doetz Reaction

抄録

Kendomycin (1), an ansa-type compoung having a unique quinone methide portion connected to a highly-substituted tetrahydropyran, was isolated from Streptomyces species. 1 possesses a potent activities as an endothelin receptor antagonist and an antiosteoporotic compoung as well as antibacterial and cytotoxic activities. Herein, we report the total synthesis of kendomycin (1) featuring the intramolecular Dotz(Doetz) reaction. We anticipated that the intramolecular Dotz reaction of Fischer chromium carbene complex 2 would afford oxametacyclophane 3 (Scheme 1). Actually, the intramolecular Dotz reaction using the simple substrate 6 produced the desired oxametzcyclophane 7 with exclusive regioselectivity (Scheme 2). Further, more complicated substrates 19 and 22 were applied to the reaction as model studies of kendomycin (1) synthesis. The intramolecular Dotz reaction of 19, containing all substituents in the tetrahydropyran portion, proceeded with high regioselectivity to give the oxametacyclophane 20 (Scheme 3). Subsequent cyclization of the product was diastereoselectively performed, affording 21. Also in the case of 22 having the foothold for the construction of the p-quinone methide portion, the intramolecular Dotz reaction proceedee with high regioselectivity to give the oxzmetacyclophane 23 (Scheme 4). The p-quinone 27 was synthesized from 23 in seven steps containing IBX oxidation of phenol. Ring closure and tautomerization was easily performed by applying 27 on the silica gel TLC to give the p-quinone methide 28. Based on the above results, we challenged the total synthesis of kendomycin (1)(Scheme 5-8). The Suzuki coupling of the left half segment 36, synthesized from 29, and the right half segment 40, derived from the ent-29, gave 41 in excellent yield. Diastereoselective tetrahydropyran-ring formation and the protecting group manipulation of 41 afforded the precursor of the chromium carbene complex. The resulting 48 was converted to the carbene complex 49 and it was subjected to the intramolecular Dotz reaction to give the desired oxametacyclophane 50 in good yield. After oxdative cleavage of terminal olefin followed by the Claisen rearrangement, the resulting 52 was oxidized with IBX and applied on silica gel, giving p-quinone methide 54. After deprotection of TBS group as the last step, we accomplished the total synthesis of kendomycin (1).

収録刊行物

詳細情報 詳細情報について

  • CRID
    1390001206078285184
  • NII論文ID
    110009757636
  • DOI
    10.24496/tennenyuki.51.0_169
  • ISSN
    24331856
  • 本文言語コード
    ja
  • データソース種別
    • JaLC
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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