Takayuki Tsuritani

Enolate formation from cyclopropyl ketones via iodide-induced ring opening and its use for stereoselective aldol reaction

Treatment of cyclopropyl ketones with TiCl4-n-Bu4NI mixed reagent provides (Z)-titanium enolates which afford syn-α-iodethyl-β-hydroxyketones stereoselectively upon subsequent reaction with various aldehydes. The aldol adducts are cyclized into trans-acyltetrahydrofurans in good yield by active alumina. In contrast, the use of Et2AlI in place of TiCl4-n-Bu4NI provides the corresponding anti aldol adducts with high stereoselectivity. These methods can complementarily provide both syn and anti isomers of α-iodoethyl-β-hydroxyketones from cyclopropyl ketones and aldehydes.

N-cyclopropylation of indoles and cyclic amides with copper(II) reagent.

Copper-mediated coupling reactions of cyclopropylboronic acid with indoles and cyclic amides are described. The process utilizes catalytic or stoichiometric amounts of copper(II) acetate, DMAP, and NaHMDS at 95 degrees C under an atmosphere containing oxygen. A variety of functional groups remain intact throughout the reaction.

Highly selective cleavage of prenyl ethers by means of a TiCl4-n-Bu4NI mixed reagent

Treatment of the prenyl ether of salicylate with a TiCl4-n-Bu4NI mixed reagent resulted in cleavage of the CO bond to provide ethyl salicylate in quantitative yield. On the other hand, no cleavage reaction was observed when ethyl p-prenyloxybenzoate was used as a substrate. In this system, the cleavage reaction of ethers proved to be accelerated by the chelating effect of a neighboring group in the substrate.

Synthesis of alpha-chloroaldoxime O-methanesulfonates and their use in the synthesis of functionalized benzimidazoles.

Three different alpha-chloroaldoxime O-methanesulfonates were synthesized to investigate their chemical properties. The compounds were found to be stable and were able to be stored at ambient temperature without any precautions. The reactions with anilines were investigated, and it was found that an additive is required to activate the sulfonate. TMEDA was found to be the most efficient additive, and various benzimidazoles were synthesized through the reaction.