An unprecedented and simple direct vinylogous addition of deconjugated butenolide to enals has been developed in excellent stereoselectivities (>95% ee), with Aminal-PYrrolidine (APY) catalyst. This methodology allows for the efficient preparation of complex γ-butenolide from readily available renewable resources. Furthermore, preliminary mechanistic investigations have allowed for the better understanding of the origin of both stereoselectivities and of the observed high reactivities.

Hydrogenation and transfer hydrogenation of imines with cyclohexa-1,4-dienes, as well as with a representative Hantzsch ester dihydrogen surrogate, are reported. Both processes are catalyzed by tethered Ru-S complexes but differ in the activation mode of the dihydrogen source: cooperative activation of the H-H bond at the Ru-S bond leads to the corresponding Ru-H complex and protonation of the sulfur atom, whereas the same cationic Ru-S catalyst abstracts a hydride from a donor-substituted cyclohexa-1,4-diene to form the neutral Ru-H complex and a low-energy Wheland intermediate. A sequence of proton and hydride transfers on the imine substrate then yields an amine. The reaction pathways are analyzed computationally, and the established mechanistic pictures are in agreement with the experimental observations.

The first organocatalytic diastereo- and enantioselective domino Michael/aldol reaction of 3-halogeno-1,2-diones to α,β-unsaturated aldehydes has been achieved. This transformation tolerates a large variety of electronically different substituents on both reactive partners and allows the synthesis of challenging cyclopentanone derivatives with four contiguous stereogenic centers in excellent diastereoselectivities (>20:1 dr) as well as good yields (69-97%), and enantioselectivities (up to 94% ee).

An enantio- and diastereoselective organocatalytic domino Michael/Aldol reaction for the direct preparation of synthetically and medicinally relevant bicyclo[3.2.1]octane derivatives with four stereogenic centers, including two quaternary carbons, has been described. The reaction tolerates a large variety of substituents on β,γ-unsaturated 1,2-ketoesters and cyclic 1,3-ketoesters. It allows for the formation of various bicyclo[3.2.1]octanes in good yields (53-98%), diastereoselectivities (1:1 to 5:1 dr), and enantioselectivities (up to 95:5 ee).

A direct construction of bicyclo[3.2.1]octanes by an organocatalytic domino Michael/Aldol reaction of cyclic 1,3-keto esters with β,γ-unsaturated 1,2-keto amides is reported. Formation of a precipitate corresponding to the racemic co-crystals of the bicyclic compound was observed in toluene, whereas a homogeneous solution was obtained in dichloromethane. Preliminary mechanistic investigations on the reversibility of the system allowed enhancing the selectivity (>20:1 dr, 73% ee). Relative configuration of the bicyclic compound was determined by X-ray crystal structure analyses