Masanori Tayu

Asymmetric Total Synthesis of (−)-Leuconoxine via Chiral Phosphoric Acid Catalyzed Desymmetrization of a Prochiral Diester

The asymmetric total synthesis of (-)-leuconoxine has been achieved. The desymmetrization of a prochiral diester using a chiral phosphoric acid catalyst produced a highly enantioenriched lactam with excellent yield. The ring construction featuring an intramolecular N-acyliminium cyclization and the one-step pyrrolidone formation using Bestmanns ylide was successfully accomplished.

Thionium-Based One-Pot Construction of Homo-/Heterodimeric Pyrroloindoline from Tryptamine

We report a one-pot procedure for forming a dimeric pyrroloindoline framework with a thionium reagent. The cyclization of tryptamine with DMSO and Tf(2)O, followed by substitution with indole derivatives, produced racemic 3a-indolylpyrroloindolines. The method enables rapid access to heterodimeric pyrroloindolines as well as to homodimeric pyrroloindolines.

Direct C2-Functionalization of Indoles Triggered by the Generation of Iminium Species from Indole and Sulfonium Salt

An indole core bearing a functional group on the C2 position is often found as a key structure in biologically active natural products and pharmaceuticals. Here, we report direct C2-functionalization of indoles triggered by the formation of an iminium species generated from indole and a sulfonium reagent. The reaction proceeded under very mild conditions to give the corresponding C2-substituted indole derivatives in good to high yields.

Total Synthesis of (+)-Gliocladin C Based on One-Pot Construction of a 3a-(3-Indolyl)pyrroloindoline Skeleton by Sulfonium-Mediated Cross-Coupling of Tryptophan and Indole

Total synthesis of (+)-gliocladin C has been achieved on the basis of one-pot construction of the 3a-(3-indolyl)pyrroloindoline core structure by the cross-coupling of a tryptophan derivative and an indole promoted by a sulfonium species generated from dialkylsulfoxide and triflic anhydride.

A metal-free biaryl coupling reaction activated by a sulfonium salt

An intermolecular biaryl coupling reaction of phenol derivatives activated by a sulfonium salt formed from diphenyl sulfoxide and trifluoromethanesulfonic anhydride has been developed. The method is a rapid, one-pot reaction leaving no trace of the sulfonium moiety in the coupling products. Tri-substituted phenyl ethers also gave coupling products in moderate yields.