Synthesis of the monomeric counterpart of Marinomycin A and B.

The synthesis of polyketide natural products has been a captivating pursuit in organic chemistry, with a particular focus on selectively introducing 1,3-polyol units. Among these natural products, Marinomycins A-D have garnered substantial interest due to their exceptional structural features and potent cytotoxicity. In this paper, we present a novel approach for synthesising the monomeric counterparts of Marinomycin A and B. Our method employs a previously established iterative cycle in conjunction with a standardised polyketide building block. Through this strategy, we showcase a promising pathway towards total and partial syntheses of these intriguing natural products.

1,2-Alkyl migration as a key element in the invention of cascade reactions catalyzed by pi-acids.

This brief overview highlights recent progress in the field of cascade reactions that are initiated by the activation of a pi-system using platinum and gold catalysts and that are coupled with a 1,2-alkyl migration step. While the reactions discussed aim to rapidly evolve molecular complexity, they are experimentally straightforward and easy to perform. Primarily guided by the type of 1,2-alkyl migration, methods are categorized as shifts to metal carbenoid centers and pinacol-type rearrangements.

Direct carbocyclization of aldehydes with alkynes: combining gold catalysis with aminocatalysis.

A combination of gold(I) complexes and amine bases catalyzes the 5-exo-dig cyclization of formyl alkynes. This direct alpha-functionalization of aldehydes with unactivated alkynes does not involve the use of preformed enol equivalents.

Synthesis of 4-iodo-3-furanones utilizing electrophile-induced tandem cyclization/1,2-migration reactions.

Two protocols for the construction of 4-iodo-3-furanones through a sequence consisting of cyclization and 1,2-migration of 2-alkynyl-2-silyloxy carbonyl compounds were developed. In one, electrophilic cyclization is directly induced by N-iodosuccinimide (NIS). In the second less limited variant, AuCl3 catalyzes the tandem reaction in the presence of NIS to provide highly substituted heterocycles in moderate to excellent yields.

A new method for the synthesis of Z-enediones via IBX-mediated oxidative rearrangement of 2-alkynyl alcohol systems.

o-Iodoxybenzoic acid (IBX) was found to mediate the conversion of alpha-alkynyl alcohols into Z-enediones under notably mild conditions via a novel rearrangement mechanism (33-65% yield, 13 examples).