Shintaro Kodama

Transition-metal-catalyzed hydrothiolation of cyclohexylallene with benzenethiol or diphenyl disulfide

The reaction of benzenethiol (or diphenyl disulfide) with cyclohexylallene, as a representative terminal allene, has been investigated in detail in the presence of transition metal-phosphine complexes as the catalyst. Pd(PPh3)4-catalyzed hydrothiolation of cyclohexylallene with benzenethiol in acetonitrile affords the corresponding terminal vinylic sulfide [RCH2C(SPh)=CH 2(R= c Hex)] regioselectively in good yield, whereas Pt(PPh3)4-catalyzed hydrothiolation of cyclohexylallene gives the regioisomeric vinyl sulfide successfully. Similar hydrothiolation of the allene proceeds using diphenyl disulfide, instead of benzenethiol, in the presence of triphenylphosphine and water.

Palladium-Catalyzed Cyanothiolation of Internal Alkynes Using Organic Disulfides and tert-Butyl Isocyanide

Despite the availability of selective synthetic approaches to multifunctionalized substituted olefins, the cyanothiolation of internal alkynes has been much less explored. Herein, we show that nonactivated internal alkynes can be successfully cyanothiolated with diaryl disulfides and tert-butyl isocyanide in the presence of a Pd catalyst (e.g., Pd(PPh3)4) with the release of isobutene and arenethiol to afford β-thiolated alkenyl cyanides in yields of 34-89%.

(2-Deoxy-2-{[2-(2-pyridinyl-κN)-4-thiazolecarbonyl-κN3]amino}-α-d-glucopyranose)dichloropalladium(II) Methanol Solvate

A novel palladium(II) complex with a glycoconjugated 2-(2-pyridyl)thiazole ligand was synthesized. Single-crystal X-ray analysis revealed a packing structure that may be stabilized by hydrogen bonding between sugar moieties and between methanol (crystal solvent) and a sugar moiety.

A Benzoyl Peroxide/Diphenyl Diselenide Binary System for Functionalization of Alkynes Leading to Alkenyl and Alkynyl Selenides

Binary systems consisting of benzoyl peroxide (BPO) and diorganyl diselenide are effective in the selective benzoyloxyselenation of internal alkynes to afford the corresponding β-(benzoyloxy)alkenyl selenides in good yields. In contrast to internal alkynes, terminal alkynes undergo a novel C(sp)-H substitution with the phenylseleno group of the BPO/(PhSe)2 system, providing alkynyl selenides in good yields. Both selenation reactions might proceed via benzoyloxy selenide (PhC(O)O-SeAr) as a key intermediate for electrophilic addition to alkynes. The products alkenyl and alkynyl selenides are expected to be useful synthetic intermediates in organic synthesis.