Shin-ichi Hirashima

Direct Aerobic Photo-Oxidative Synthesis of Aromatic Methyl Esters from Methyl Aromatics via Dimethyl Acetals

A useful method for facile synthesis of aromatic methyl esters from methyl aromatics via dimethyl acetals by aerobic photo-oxidation using inexpensive and easily handled CBr(4) as catalyst is reported. This is the first example for direct preparation of the corresponding aromatic methyl esters from methyl aromatics.

One-pot metal-free syntheses of acetophenones from styrenes through aerobic photo-oxidation and deiodination with iodine.

A one-pot synthetic protocol of acetophenones from styrenes with molecular oxygen, visible light, and molecular iodine is reported. This procedure involves aerobic photo-oxidation and deiodination in one pot and provides the first report of metal-free direct syntheses of acetophenones from styrenes.

Squaramide–Sulfonamide Organocatalyst for Asymmetric Direct Vinylogous Aldol Reactions

Asymmetric direct vinylogous aldol reactions of furan-2(5H)-one with aldehydes in the presence of a catalytic amount of novel squaramide-sulfonamide organocatalyst resulted in the corresponding addition products with high to excellent enantioselectivities. This is the first successful report illustrating an example of highly stereoselective reactions using a squaramide-sulfonamide organocatalyst.

Perfluoroalkanesulfonamide Organocatalysts for Asymmetric Conjugate Additions of Branched Aldehydes to Vinyl Sulfones

Asymmetric conjugate additions of branched aldehydes to vinyl sulfones promoted by sulfonamide organocatalyst 6 or 7 have been developed, allowing facile synthesis of the corresponding adducts with all-carbon quaternary stereocenters in excellent yields with up to 95% ee.

Asymmetric Conjugate Addition of Nitroalkanes to Enones Using a Sulfonamide–Thiourea Organocatalyst

The asymmetric conjugate addition of nitroalkanes to α,β-unsaturated ketones in the presence of a catalytic amount of a novel sulfonamide-thiourea organocatalyst resulted in the corresponding γ-nitro carbonyl products in high yields with excellent enantioselectivities (up to 97% ee).

Cinchona–Diaminomethylenemalononitrile Organocatalyst for the Highly Enantioselective Hydrophosphonylation of Ketones and Enones

The use of diaminomethylenemalononitrile (DMM) organocatalyst to promote the challenging 1,2-hydrophosphonylation of simple ketones and enones, which are also called α,β-unsaturated ketones, is proposed and validated. This reaction provided the corresponding chiral α-hydroxy phosphonates in high to excellent yields and with enantioselectivity up to 96% ee.

Asymmetric conjugate addition of α-cyanoketones to enones using diaminomethylenemalononitrile organocatalyst

A diaminomethylenemalononitrile organocatalyst efficiently catalyzed the asymmetric conjugate addition of α-cyanoketones to vinyl ketones to give the corresponding 1,5-dicarbonyl compounds, which bear an all-carbon quaternary stereogenic center with high enantioselectivities. This report is the first example of the asymmetric conjugate addition of α-cyanoketones to vinyl ketones using an organocatalyst.

Asymmetric Conjugate Additions of Carbonyl Compounds to Nitroalkenes under Solvent-Free Conditions Using Fluorous Diaminomethylenemalononitrile Organocatalyst

The novel fluorous organocatalyst bearing a diaminomethylenemalononitrile motif is prepared. The fluorous organocatalyst efficiently promotes asymmetric conjugate additions of ketones to nitroalkenes and results in high yields of these addition products with excellent enantioselectivities under solvent-free conditions.