Hg(OTf)2-catalyzed aryl–allene cyclization accompanied by formation of a quaternary carbon center has been realized. Deuterium-labeling experiments and computational modeling were used to propose a novel catalytic pathway involving direct H-transfer from the aromatic ring to the vinyl mercury moiety followed by mercury 1,2-migration.

Development of reusable heterogeneous catalysts has attracted a great deal of attention for both environmental and atom-economic reasons. In particular, a considerable amount of work has focused on reusable heavy- and rare-metal catalysts in order to limit the use and/or minimize the generation of problematic metal waste upon disposal. Herein is reported the development of a new polysiloxane-linked m-carbaboranylmercury (SiCB–Hg) catalyst, which can be used for various mercury salt-induced reactions such as the regioselective cyclization of 1,3-dienes and allyl alcohols, the intermolecular amination of allyl alcohols with sulfamates, and the cycloisomerization of alkynes. The catalyst can be completely recovered by simple filtration, with residual mercury in the filtrate <0.001% (nearly the quantitative limit). Furthermore, the catalyst can be reactivated by treatment with aqueous HCl and then AgOTf for reuse.

(−)-Thallusin, isolated from a marine bacterium, is the only known natural product to act as an algal morphogenesis inducer. Because (−)-thallusin can only be obtained in exceedingly limited amounts from microbial cultivation, a synthetic supply of this compound is highly desirable. Here, we describe a novel synthetic pathway to (±)-thallusin and the first asymmetric synthesis of (−)-thallusin utilizing the enzymatic hydrolysis resolution with the combination of lipase PS-30 and lipase M Amamo-10.

Vizantin, 6,6′-bis-O-(3-nonyldodecanoyl)-α,α′-trehalose, was developed as a safe immunostimulator on the basis of a structure–activity relationship (SAR) study with trehalose 6,6′-dicorynomycolate (TDCM). It was possible to synthesize vizantin on a large scale more easily than in the case of TDCM, and the compound exhibited more potent prophylactic effect on experimental lung metastasis of B16–F0 melanoma cells. Because vizantin stimulated human macrophages, it is a promising candidate for clinical application.

The combination of carbaboranylmercuric chloride (new type of bulky Lewis acid) and silver triflate efficiently catalyzes cycloisomerization of 1,3-dienes at room temperature. The catalytic system gives allyl-substituted azacycles and cycloalkanes in excellent yields with high to complete regioselectivity.