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The first total syntheses of corallocins B and C are described herein. The Suzuki–Miyaura coupling was key to completion. Because these two natural products have been reported to induce neurotrophin expression in human astrocytes, they are expected to serve as new drug leads for neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Herein, we describe the first total synthesis of cochlearol B, a meroterpenoid natural product featuring a 4/5/6/6/6‐fused pentacyclic structure. Key steps, oxidative cyclization and subsequent intramolecular [2+2] photocycloaddition, which constructed the pentacyclic structure in highly stereoselective manner, allowed efficient access to cochlearol B with the longest linear sequence of 16 steps, and in 9 % overall yield. Single‐crystal X‐ray crystallographic analysis clearly confirmed the stereochemistry of cochlearol B. [ABSTRACT FROM AUTHOR]

In this paper, the synthesis of the carbon skeleton of cotylenin A aglycone is described. The key reactions, including an intramolecular aldol reaction, an aldol coupling reaction, and a ring-closing meta-thesis, allow for the effective and stereoselective access to the carbon skeleton of cotylenin A aglycone. The stereochemistry was confirmed by single-crystal X-ray crystallographic analyses of related compounds. [ABSTRACT FROM AUTHOR]

Highly diastereoselective total syntheses of (±)‐caseabalansin A (1) and (±)‐18‐epicaseabalansin A (2) are described in this paper. We revealed that the intramolecular Robinson‐type annulation of an alkynone was effective in the stereocontrolled construction of the bicyclic skeleton of 1 and 2. Further transformation of the resulting enone, including diastereoselective reduction by LiAlH(OtBu)3, hydroxy‐group‐directed hydrogenation, cyclization to form the cyclic acetal moiety, and introduction of a side chain by a C(sp3)−C(sp3) Stille coupling reaction, resulted in the total syntheses of (±)‐1 and (±)‐2. [ABSTRACT FROM AUTHOR]