First total synthesis of salinipyrone A using highly stereoselective vinylogous Mukaiyama aldol reaction

Facile construction of 2-pyrones under carbene catalysis

2-Pyrones are valuable structural motifs in organic chemistry, found in numerous natural products and pharmaceuticals. The synthesis of these heterocycles has been significantly advanced by the application of N-Heterocyclic Carbene (NHC) catalysis. This review examines the recent advancements in NHC-catalyzed synthesis of 2-pyrones, highlighting key methodologies, mechanisms, and synthetic applications. NHC catalysis has revolutionized the synthesis of 2-pyrones, providing efficient, selective, and versatile methods for constructing these valuable heterocycles.

Development of α,α-Disubstituted Crotylboronate Reagents and Stereoselective Crotylation via Brønsted or Lewis Acid Catalysis

The development of α,α-disubstituted crotylboronate reagents is reported. Chiral Brønsted acid-catalyzed asymmetric aldehyde addition with the developed E-crotylboron reagent gave (E)-anti-1,2-oxaborinan-3-enes with excellent enantioselectivities and E-selectivities. With BF₃·OEt₂ catalysis, the stereoselectivity is reversed, and (Z)-δ-boryl-anti-homoallylic alcohols are obtained with excellent Z-selectivities from the same E-crotylboron reagent. The Z-crotylboron reagent also participates in BF₃·OEt₂-catalyzed crotylation to furnish (Z)-δ-boryl-syn-homoallylic alcohols with good Z-selectivities. DFT computations establish the origins of observed enantio- and stereoselectivities of chiral Brønsted acid-catalyzed asymmetric allylation. Stereochemical models for BF₃·OEt₂-catalyzed reactions are proposed to rationalize the Z-selective allyl additions. These reactions generate highly valuable homoallylic alcohol products with a stereodefined trisubstituted alkene unit. The synthetic utility is further demonstrated by the total syntheses of salinipyrones A and B.

Marine natural products

This review covers the literature published in 2012 for marine natural products, with 1035 citations (673 for the period January to December 2012) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1241 for 2012), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

The vinylogous Mukaiyama aldol reaction (VMAR) in natural product synthesis

This review will provide an overview on the recent developments of polyketide synthesis using the vinylogous Mukaiyama aldol reaction for the construction of advanced intermediates. In general, four different motifs can be constructed efficiently using the recent developments of asymmetric variants of this strategy.