Selenides, diphenyl synthesis

Alkenes from organomercurials.1 Photoinitiated reaction of diphenyl diselenide with the organomercurial 1 provides a mixture of the corresponding a- and P-phenyl selenides, which undergo oxidative elimination to 2. The reaction provides a key step in a total synthesis of K-76 (3), which counteracts the inflammatory... 

Although phenylsenenyl radicals can be generated easily by irradiation of diphenyl diselenide, their low reactivity toward unactivated alkenes and alkynes has prevented their extensive use in synthesis.267,268 But diphenyl diselenide can be used as an efficient trap for alkyl radicals. The products are alkyl phenyl selenides. This trapping reaction has found application to different radical reactions and the selenides obtained by this reaction can be used in subsequent reactions. 

The recent synthesis of lycorine (8) from the lactam (5) (cf. Vol. 10, p. 136) has now been modified by conversion of the six-membered lactam (5) into the five-membered lactam (6).4 Functionalization of ring C by the epoxidation-diphenyl selenide procedure, as in the earlier synthesis, gave the lactam (7), which was reduced to lycorine (Scheme 1). 

Reaction of diphenyl diselenide or dimethyl diselenide with hydrazine hydrate and sodium hydroxide generates the corresponding selenolates smoothly in solvents like DMF or diethyl ether and in the presence of tetrabutylammonium chloride as a phase-transfer catalyst [13]. The selenolates react with organic halides to give various selenides (Scheme 9). Similar conditions have been applied to the synthesis of aryl vinyl selenides from diaryl diselenides and acetylene [14]. 

A new one-pot method has been developed by Kraszewski for the synthesis of aryl nucleoside phosphate (3a-p) and phosphorothioate (4a-p) diesters. This method, based on H-phosphonate chemistry, employed diphenyl phosphoroch-loridate and a series of phenols. Depending on the substituents present on the phenols, oxidation conditions were optimized to avoid competing hydrolysis. A versatile procedure that permits easy access to H-phosphonoselenoate monoesters (5) has been developed by Stawinski. These monoesters, obtained by selenisation of a phosphinate using triphenylphosphine selenide in combination with trimethylsilyl chloride, reacted with a suitable nucleoside in pyridine/acetonitrile in the presence of diphenyl phosphorochloridate to yield... 

Several sulfenyl group sources are also known [60,61]. Diphenyl selenide was reported [52]. Diphenylphosphorus chloride was used extensively in the synthesis of new phosphines [38,47,51,62]. A chiral version is shown in Eq. (6) [51]. 

Wang ZL, Tang RY, Luo PS, Deng SL, Zhong P, Li JH. Hydrothiolation of terminal alkynes with diaryl disulfides and diphenyl diselenide selective synthesis of (Z)-l-alkenyl sulfides and selenides. Tetrahedron 2008 64 10670-10675. 

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