Erli Sugiono

Enantioselective Organocatalytic Synthesis of Quaternary α-Amino Acids Bearing a CF3 Moiety

A highly enantioselective Friedel-Crafts reaction catalyzed by a chiral phosphoric acid was developed. N-Boc-protected ethyl trifluoropyruvate imine was activated by 6 mol % of catalyst and reacted with a wide variety of indole derivatives to afford quaternary α-amino acids in excellent yields (up to 99%) and high enantioselectivities (up to 98:2 er).

Shedding light on organocatalysis-light-assisted asymmetric ion-pair catalysis for the enantioselective hydrogenation of pyrylium ions.

A new light-driven asymmetric ion-pair catalysis procedure for the metal-free enantioselective hydrogenation of in situ generated pyrylium ions from readily available chalcones was developed (see scheme). The photo-assisted Brønsted acid catalyzed procedure has broad scope and allows, for the first time, access to valuable 4H-chromenes in good yields and with excellent enantioselectivities.

Unifying Metal‐ and Organocatalysis for Asymmetric Oxidative Iminium Activation: A Relay Catalytic System Enabling the Combined Allylic Oxidation of Alcohols and Prolinol Ether Catalyzed Iminium Reactions

A multicatalytic system consisting of tetrapropylammonium perruthenate/N-methylmorpholine N-oxide (TPAP/NMO) as oxidant, and diarylprolinol TMS-ether as chiral amine catalyst, has been developed and applied in the efficient construction of valuable chiral molecules. The one-pot domino reactions elaborated in the present study are based on the in situ generation of α,β-unsaturated aldehydes from allylic alcohols and their subsequent use in various asymmetric transformations (e.g., cyclopropanation, Michael addition, Michael addition/acetalization). TPAP as a substrate-selective redox catalyst is well tolerated by the amine catalyst and the domino reactions proceed in good yields and high enantioselectivities. The compatibility of metal and organocatalysis presented herein widens the scope of asymmetric iminium catalysis.

Continuous-flow catalytic asymmetric hydrogenations: Reaction optimization using FTIR inline analysis

Summary The asymmetric organocatalytic hydrogenation of benzoxazines, quinolines, quinoxalines and 3H-indoles in continuous-flow microreactors has been developed. Reaction monitoring was achieved by using an inline ReactIR flow cell, which allows fast and convenient optimization of reaction parameters. The reductions proceeded well, and the desired products were isolated in high yields and with excellent enantioselectivities.

Online monitoring and analysis for autonomous continuous flow self-optimizing reactor systems

In this review the recent progress in the field of self-optimizing reactor systems for continuous flow chemistry is presented. Particular focus is directed to the implementation of monitoring tools and realization of computer-controlled reaction optimizations without human interaction.

Catalytic Asymmetric Synthesis of Chromene Derivatives by Iminium Ion Catalysis

The diarylprolinol TMS ether catalyzed enantioselective addition–acetalization cascade reaction of 1,3‐diketones with α,β‐unsaturated aldehydes provides access to biologically active hydroxychromenone derivatives. These chromenones can be converted into the corresponding lactones, oxadecalinones, and benzopyranes in good yields without loss of enantiomeric excess. The usefulness of this newly developed methodology was demonstrated in the synthesis of the core structure of a Δ9‐tetrahydrocannabinol analog.

Two polymorphs of 4-propyl-3,4-dihydro-2H-naphtho[1,2-b]pyran-5,6-dione.

Two polymorphs of the title compound, C(16)H(16)O(3), have been obtained from the same solution. One polymorph, (I(m)), crystallizes in the monoclinic space group P2(1), while the other, (I(o)), crystallizes in the orthorhombic space group P2(1)2(1)2(1). The cell constants of the two polymorphs are surprisingly similar. Whereas the a and b axes are equal in the two structures, the c axis in (I(o)) is twice as long as that in (I(m)). The monoclinic angle beta is 95.084 (9) degrees compared with 90 degrees in the orthorhombic crystal system. The cell volume of (I(m)) is almost exactly half of the cell volume of (I(o)). The packing motifs are also very similar in the two structures. However, whereas the molecules in (I(m)) are related by a twofold screw axis just in the direction of the b axis, in (I(o)) there are twofold screw axes along all three directions of the unit cell.

Connecting Curable Siloxanes to Luminescent Organic Semiconductors - Monomers for Functional Hybrid Materials

Luminescent stilbenoid chromophores with two alkoxysilane end groups are prepared via hydrosilylation or condensation / reduction of substituted 5-ring OPVs with hydro- and aminopropylsilanes. Chromophore and curable units are connected via flexible spacers. To obtain compounds with a rigid connection between silane and π-system, iodo- or bromo-OPVs were coupled to alkoxysilanes carrying vinyl- or p -vinylphenyl moieties under Heck conditions. This approach allowed a combined connection of the chromophore to the silane moiety with an extension of the π-system. Hydrolysis of the alkoxysilanes yields silanols condensing to curable three-dimensional networks, thus allowing the transformation of small molecules to transparent and fluorescent films with well-defined chromophores.