Vinylogous and arylogous stereoselective base-promoted phase-transfer catalysis

Vinylogous enolate and enolate-type carbanions, generated by deprotonation of α,β-un-saturated compounds and characterized by delocalization of the negative charge over two or more carbon atoms, are extensively used in organic synthesis, enabling functionalization and C–C bond formation at remote positions. Similarly, reactions with electrophiles at benzylic and heterobenzylic position are performed through generation of arylogous and heteroarylogous enolate-type nucleo-philes. Although widely exploited in metal-catalysis and organocatalysis, it is only in recent years that the vinylogy and arylogy principles have been translated fruitfully in phase-transfer catalyzed processes. This review provides an overview of the methods developed to date, involving vinylo-gous and (hetero)arylogous carbon nucleophiles under phase-transfer catalytic conditions, high-lighting main mechanistic aspects.