The domino reaction of 2,3-epoxy-1-alcohol derivatives, namely tetrasubstituted 2,3-epoxy-1-alcohols and 2- or 3-alkyl trisubstituted 2,3-epoxy-1-alcohols, with PhI(OCOCF(3))(2) in the presence of H(2)O is described in detail. In this reaction, several types of lactol derivatives can be directly obtained from the 2,3-epoxy-1-alcohol derivatives in a single operation. The obtained lactols were successively converted into the corresponding lactones. This reaction is applicable to the construction of optically active lactone compounds. The asymmetric total synthesis of (+)-tanikolide, an antifungal marine natural product, has been effectively achieved by using this reaction.

The domino reaction can perform several reactions in a single operation and is a very powerful tool to synthesize organic compounds. The development of new and efficient domino

The domino reaction can perform several reactions in a single operation and is a very powerful tool to synthesize organic compounds. The development of new and efficient domino

Synthesis of (+)-Tanikolide. -The domino reaction of 2-(III) or 3-alkyl 2,3-epoxy-1-alcohols (VI) with phenyliodonium trifluoroacetate (PIFA) provides access towards lactols (IV) as well as bicyclic lactols (VII), resp., on different pathways. The reaction mechanism is discussed in detail. Both types of lactols can be converted to the corresponding lactones. In the case of bicyclic lactols (VII), however, a reductive dioxole ring opening precedes the lactone formation. This method is successfully applied in an asymmetric synthesis of (+)-tanikolide (XI). -(FUJIOKA, H.; MATSUDA, S.; HORAI, M.; FUJII, E.; MORISHITA, M.; NISHIGUCHI, N.; HATA, K.; KITA*, Y.; Chem. Eur. J. 13 (2007) 18, 5238-5248; Grad. Sch. Pharm. Sci., Osaka Univ., Suita, Osaka 565, Japan; Eng.) -Mischke 41-111

Synthesis of (+)-Tanikolide. -2,3-Epoxy-1-alcohols are transformed into lactols via a three-or four-step sequence in a single operation. The generality is examined using various types of epoxy alcohols. The bicyclic substrates (I) give keto lactols (II) in fairly good yields. The bicyclic dioxaspiro lactols (V) are obtained in good yields from epoxy alcohols (IV). The formation of (V) is rationalized as a further lactol formation between the hemiacetal hydroxy function and the interim formed aldehyde. Furthermore, the method is applied to the concise asymmetric synthesis of (+)-tanikolide (IX). -(KITA, Y.; MATSUDA, S.; FUJII, E.; HORAI, M.; HATA, K.; FUJIOKA, H.; Angew. Chem., Int. Ed. 44 (2005) 36, 5857-5860; Grad. Sch. Pharm.