Synthesis of Waixenicin A: Exploring Strategies for Nine-Membered Ring Formation.

We present a comprehensive account on our efforts behind the recently published synthesis of waixenicin A. Our approach for constructing the dihydropyran ring relied on an Achmatowicz rearrangement. For the assembly of the nine-membered ring, four distinct strategies were investigated.

Synthesis of (-)-Mitrephorone A via a Bioinspired Late Stage C-H Oxidation of (-)-Mitrephorone B.

We present a bioinspired late-stage C-H oxidation of the -trachylobane natural product mitrephorone B to mitrephorone A. The realization of this unprecedented transformation was accomplished by either an iron-catalyzed or electrochemical oxidation and enabled access to the densely substituted oxetane in one step. Formation of mitrephorone C, which is lacking the central oxetane unit but features a keto-function at C2, was not formed under these conditions.

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms.

This review describes strategies for the chemical synthesis of xenicane diterpenoids and structurally related metabolites. Selected members from the four different subclasses of the Xenia diterpenoid family, the xenicins, xeniolides, xeniaphyllanes and xeniaethers, are presented. The synthetic strategies are discussed with an emphasis on the individual key reactions for the construction of the uncommon nine-membered carbocycle which is the characteristic structural feature of these natural products.

Intramolecular vinyl quinone Diels-Alder reactions: asymmetric entry to the cordiachrome core and synthesis of (-)-isoglaziovianol.

A short and asymmetric entry to the core structure of the cordiachromes has been developed, allowing access to (-)-isoglaziovianol in seven steps. Our synthesis includes a Trost asymmetric allylic alkylation and a reaction cascade triggered by a vinyl quinone Diels-Alder reaction and followed by intramolecular nucleophilic interception.