Adrien Quintard

Highly Enantioselective Direct Vinylogous Michael Addition of γ-Butenolide to Enals

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.

Access to High Levels of Molecular Complexity by One-Pot Iridium/Enamine Asymmetric Catalysis†

Independent workers with team spirit: A catalytic sequence that exploits the compatibility of (chiral) cationic iridium catalysts for the isomerization of primary allylic alcohols to aldehydes with organocatalysts has been developed for the highly enantioselective α functionalization of aldehydes (see scheme: up to 66 % yield, d.r. 49:1, 99 % ee). The reaction displayed useful generality with respect to both the nucleophile and the electrophile.

Iron Cyclopentadienone Complexes: Discovery, Properties, and Catalytic Reactivity

Iron cyclopentadienone complexes have recently received particular attention in organic chemistry. This is due to their easy synthesis from simple and cheap materials, air-water stability, and most importantly for their unique catalytic features arising from the presence of a non-innocent ligand, triggering powerful redox properties. Herein we discuss the properties of such complexes from synthetic and mechanistic points of view, and their applications in original redox-neutral transformations in both racemic and enantioselective series.

Diversity‐Oriented Synthesis towards Conceptually New Highly Modular Aminal–Pyrrolidine Organocatalysts

A conceptually new family of modular aminal-pyrrolidine organocatalysts was prepared by diversity-oriented synthesis. The catalytic properties of these organocatalysts could easily be tuned by varying the different substituents on the aminal part. Good yields and enantioselectivities up to 91 % were obtained in Michael additions to nitroolefins or vinyl sulfones.

An iron/amine-catalyzed cascade process for the enantioselective functionalization of allylic alcohols.

Three is a lucky number: An enantioselective transformation of allylic alcohols into β-chiral saturated alcohols has been developed by combining two distinct metal- and organocatalyzed catalytic cycles. This waste-free triple cascade process merges an iron-catalyzed borrowing-hydrogen step with an aminocatalyzed nucleophilic addition reaction.

Asymmetric Organocatalytic 1,6‐Conjugate Addition of Aldehydes to Dienic Sulfones

An unprecedented 1,6-enamine conjugate addition exploiting the charge delocalization in 1,3-bis(sulfonyl) butadienes has been developed. By appropriately designing a Michael acceptor, unique reactivities were obtained for the formation of highly valuable dienes containing two versatile vinyl sulfones (see scheme, TMS=trimethylsilyl).

Copper-catalyzed enantioselective 1,4-addition to α,β-unsaturated aldehydes

The first asymmetric Cu-catalyzed conjugate addition of dialkylzinc zinc reagents to a large scope of enals in presence of phosphoramidite, SimplePhos, or (R)-BINAP ligands with enantiomeric excesses up to 90% is reported. Moreover, ACA of Grignard reagents afforded moderate to good 1,4-regioselectivities with enantioselectivities up to 90%.

Asymmetric catalytic alkynylation of acetaldehyde: application to the synthesis of (+)-tetrahydropyrenophorol.

By controlling the kinetics of alkynylation over aldolisation (by slowing adding the acceptor), the challenging asymmetric catalytic alkynylation of acetaldehyde has been realized. This protocol yields the corresponding attractive synthons in good to excellent enantiocontrol and shows broad tolerance and applicability. This was highlighted by its application to the synthesis of several natural products such as the rapid construction of the macrocyclic diolide (+)-tetrahydropyrenophorol.

Organocatalytic Addition on 1,2-Bis(sulfone)vinylenes Leading to an Unprecedented Rearrangement

An unprecedented rearrangement of 1,2-bis(sulfone)vinylenes used in aminocatalysis led to the formation of highly useful gem-disulfones. By using aminal-pyrrolidine organocatalysts, the 1,2-sulfone shift was generalised, leading to highly versatile adducts using both ketones and aldehydes. It represents a valuable alternative for the -alkylation of carbonyl compounds.

A Step into an eco‐Compatible Future: Iron‐ and Cobalt‐catalyzed Borrowing Hydrogen Transformation

Living on borrowed hydrogen: Recent developments in iron- and cobalt-catalyzed borrowing hydrogen have shown that economically reliable catalysts can be used in this type of waste-free reactions. By using well-defined inexpensive catalysts, known reactions can now be run efficiently without the necessary use of noble metals; however, in addition new types of reactivity can also be discovered.