Nucleophile-nucleophile coupling is ac hallenging transformation in organic chemistry.Herein we present anovel umpolung strategy for a-functionalization of aldehydes with nucleophiles.T he strategy uses organocatalytic enamine activation and quinone-promoted oxidation to access O-bound quinol-intermediates that undergo nucleophilic substitution reactions.T hese quinol-intermediates react with different classes of nucleophiles.T he focus is on an unprecedented organocatalytic oxidative a-thiolation of aldehydes.T he reaction scope is demonstrated for ab road range of thiols and extended to chemoselective bioconjugation, and applicable to alarge variety of aldehydes.This strategy can also encompass organocatalytic enantioselective coupling of a-branched aldehydes with thiols forming quaternary thioethers.S tudies indicate as tereoselective formation of the intermediate followed by as tereospecific nucleophilic substitution reaction at aquaternary stereocenter,w ith inversion of configuration.

A novel alkyl functionalization of unactivated alkyl quinolines has been developed combining InCl activation with organocatalytic activation of α,β-unsaturated aldehydes in a synergistic fashion. The reaction proceeds in a highly stereoselective manner as a sequence involving two consecutive synergistic catalytic cycles (Lewis acid- and iminium ion-catalyzed) and requires neither pre-activated alkyl quinoline substrates with electron-withdrawing substituents nor highly activated electrophiles. The reaction provides selectively double- or mono-addition products in good yields and high to excellent stereoselectivities. Furthermore, based on spectroscopic and labelling experiments, the mechanisms for the reactions are discussed.

An organocatalyzed asymmetric [4+2]-cycloaddition between tropolones and electron-deficient dienophiles is presented. Complex and biologically interesting dihydrohomobarrelenone scaffolds are formed through a Diels-Alder reaction utilizing bifunctional Brønsted-base catalysis, affording the corresponding bridged bicyclic cycloadducts in up to quantitative yields with good enantio- (up to 92 % ee) and diastereoselectivity (up to >20:1 d.r.). The synthetic value of the obtained products is explored by downstream transformations, including photoisomerizations, and their biological relevancy by in vivo testing in MCF-7 cancer cells.

Oxadendralenes are integrated in a novel manner into a one-pot cascade utilizing synergistic catalysis for the construction of valuable and complex bicyclic heterocyclic scaffolds.

The development of an organocatalytic one-pot cascade for the annulation of simple starting materials: α,β-unsaturated aldehydes, hydrogen peroxide, β-carbonyl compounds and NBS to furnish optically active 3-pyrones in good yield and with excellent enantioselectivity is presented. Further diversification of the obtained products is demonstrated by selective reductive transformations.