The principle of vinylogy states that the electronic effects of a functional group in a molecule are possibly transmitted to a distal position through interposed conjugated multiple bonds. As an emblematic case, the nucleophilic character of a π-extended enolate-type chain system may be relayed from the legitimate α-site to the vinylogous γ, ε, ..., ω remote carbon sites along the chain, provided that suitable HOMO-raising strategies are adopted to transform the unsaturated pronucleophilic precursors into the reactive polyenolate species. On the other hand, when “unnatural” carbonyl ipso-sites are activated as nucleophiles (umpolung), vinylogation extends the nucleophilic character to “unnatural” β, δ, ... remote sites. Merging the principle of vinylogy with activation modalities and concepts such as iminium ion/enamine organocatalysis, NHC-organocatalysis, cooperative organo/metal catalysis, bifunctional organocatalysis, dicyanoalkylidene activation, and organocascade reactions represents an impressive step forward for all vinylogous transformations. This review article celebrates this evolutionary progress, by collecting, comparing, and critically describing the achievements made over the nine year period 2010–2018, in the generation of vinylogous enolate-type donor substrates and their use in chemical synthesis.

The aim of this review is to highlight the utility of a remarkable triad of 2-silyloxy diene synthons derived from furan, pyrrole and thiophene in organic synthesis. These heterocycles, in reacting with a number of carbonyl-related compounds (aldehydes, imines, heteroatom-stabilized carbenium ions), act as vinylogous nucleophile modules giving rise to a myriad of functionality-rich aldol-type constructs. These, in turn, represent invaluable synthetic platforms onto which a limitless number of functional elements and chosen chirality may be introduced. Eleven syntheses, amongst the most appealing of 1991–1999, have been chosen to illustrate the potentiality of silyloxy diene chemistry.

The synthetic versatility of a special collection of heterocyclic dienoxysilane synthons based on furan, pyrrole, and thiophene to access valuable building blocks to be used in the fabrication of complex molecular architectures is featured. Accessed by base-assisted enolsilylation of α,β-unsaturated lactone or lactam precursors, siloxydiene heterocycles easily couple in a strictly vinylogous sense to diverse electrophiles, such as aldol-, Mannich-, and Michael-type acceptors, to generate butenolide-type intermediates for viable use in asymmetric synthesis. A survey of our own achievements in this area, along with preeminent contributions by other research groups reveal the unique merits of siloxydiene chemistry and highlight these reactions as a key gateway to an array of multifunctional natural or natural-like constructs. 1 Introduction 2 Synthetic Applications 2.1 Vinylogous Mukaiyama Aldol-type Additions 2.2 Vinylogous Mukaiyama Mannich-type Additions 2.3 Vinylogous Mukaiyama Michael-type Additions 3 Prospects, Challenges, and Opportunities 4 Addendum