ChemInform Abstract: Efficient Catalytic Selenolactonization—Deselenenylation Reactions Using Various Organoselenium Catalysts and Their Application to Solid‐Phase Conversion.

Fujita, Ken‐ichi; Taka, Hideo; Oishi, Akihiro; Ikeda, Yoshikazu; Taguchi, Yoichi; Fujie, Koichi; Saeki, Takashi; Sakuma, Motonari

doi:10.1002/chin.200105092

Cited by 10 publications

(16 citation statements)

References 1 publication

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“…The product was recrystallized from hot water to yield the title compound 5 as white crystals (20 mg, 76% yield). IR (film): 2919,2850,1793,1778,1716,1654,1559,1540,1510,1458,1419,1290,1182,927 3,175.3,173.9,88.1,52.5,33.3,30.9,30.8,30.8,30.7,30.6,30.5,29.2,29.0,29.0,23.9,14.7;HRMS (FAB+) 2956, 2849, 1783, 1739, 1603, 1437, 1247, 1189, 1086, 1031, 917.8 1, 170.5, 169.4, 166.9, 153.8, 122.9, 88.9, 53.8, 53.3, 43.5, 39.9; HRMS (EI+) exact mass calc'd for 2922, 2852, 1777, 1742, 1724, 1439, 1260, 1186, 1101, 968.8, 916.5, 833 8,170.2,167.4,153.3,134.5,125.3,122.8,89.6,53.7,52.5,50.1,32.7,32.0,29.5,29.4,29.3,29.3,22.9,14.3;HRMS (EI)…”

Section: (3s 2'r)-4-methyl-3-(5-oxo-25-dihydro-furan-2-yl)-pentanal (mentioning

confidence: 99%

The First Enantioselective Organocatalytic Mukaiyama−Michael Reaction: A Direct Method for the Synthesis of Enantioenriched γ-Butenolide Architecture

2003

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Section: (3s 2'r)-4-methyl-3-(5-oxo-25-dihydro-furan-2-yl)-pentanal (mentioning

confidence: 99%

The First Enantioselective Organocatalytic Mukaiyama−Michael Reaction: A Direct Method for the Synthesis of Enantioenriched γ-Butenolide Architecture

2003

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“…13 Interestingly, when the reaction mixture was allowed to stir-heat longer (17 hours), the deselenylated lactone 20 was observed as the only product and isolated in 95% yield (Table 1, entry 9). 14 Oxidative elimination 15 of the selenium species were carried out for a few selected examples given below in Table 2. Thus, substrate 9 in a CH 2 Cl 2 solution was added to pyridine (two equivalents) followed by aqueous 30% hydrogen peroxide after 20 minutes to afford the corresponding pure a,b-unsaturated ketone 21 in 97% yield (Table 2, entry 1).…”

Section: Scheme 1 Synthesis Of Odorless Diselenidementioning

confidence: 99%

“…1 H NMR (400 MHz): 2 H,3 H,4 H,0.29 [s,9 H,Si(CH 3 ) 3 ]. 13 6, 85 (11), 83 (14), 77 (30), 71 (10), 57 (14). HRMS (EI): m/z calcd for C 16 H 18 OSiS: 286.0848; found: 286.0845.…”

Section: Ir (Chcl 3 )mentioning

confidence: 99%

Odorless Diphenyl Diselenide and Disulfide: Syntheses and Applications

Patra¹,

Shanmugasundaram²,

Matoba³

et al. 2005

Synthesis

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phenyl]diselenide (3) and bis [4-(trimethylsilyl)phenyl]disulfide (31) are found to be odorless equivalents of the commonly used diphenyl diselenide and diphenyl disulfide, respectively. The diselenide 3 is shown to be useful in the preparation of odorless selenium(II) chloride 26 and selenium(IV) trichloride 28 that follow similar reactivity patterns to their phenyl derivatives and can be stored refrigerated under dry conditions. The corresponding selenium(II) bromide had to be prepared fresh from 3 before use. It is also shown that the trimethylsilyl group in the sulfide products can be protodesilylated quantitatively using TFA.The versatility and the overall synthetic utility of various reagents containing selenium and sulfur have been exemplified in their increasing use in synthesis. 1 Especially in the synthesis of complex natural products, these reagents have been indispensable. 2 During the last three decades we have seen the literature flooded with papers containing selenium-based reagents. Why has this exotic element, a member of the well known family of chalcogens, enjoyed such interest, even though the known toxicity of organoselenium compounds called for caution and their malodorous reputation made them doubly unattractive to any chemist who wanted a social life outside the laboratory? This is due to the mixed metallic and non-metallic nature of the element, its unique reactivity towards oxidation and reduction and the capacity of the selenium-based reagents to perform highly chemoselective transformations. 1,3 Among the selenium reagents, diphenyl diselenide is commonly employed for organoselenylation reactions because of its versatile reactivity (nucleophilic as well as electrophilic) depending on the reaction conditions and thus allows a myriad of transformations through a-seleno carbanions, 4 a-seleno carbeniums 5 and a-seleno carboncentered radicals. 6 Similarly, diphenyl disulfide is an important and powerful reagent for phenyl sulfanylation and related reactions that has closely followed the former in various applications. 7 The malodorous nature of these reagents has remained a potential drawback and it was only in 1998 that Nicolaou, Ruhland et al. expedited the polymer-supported selenium reagents that were odorless. 8During the last few years, we have systematically studied and developed odorless thiol and sulfide reagents and attempted to replace the commonly used malodorous sulfur reagents with odorless equivalents. 9 By elongating the carbon chain or substituting the aromatic ring with n-heptyl or, more effectively, a trimethylsilyl group (in the case of benzene and benzyl thiols), we found a surprising reduction of odor or no odor at all. 9f,10 In this paper, we present our successful approach to replace the foul smelling diphenyl diselenide and disulfide with bis[4-(trimethylsilyl)phenyl]diselenide and bis[4-(trimethylsilyl)phenyl]disulfide, respectively. Their syntheses and applications in various reactions are presented. Bis[4-(trimethylsilyl)phenyl]diselenideThe starting 1-bromo-4-(...

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“…This resulted in selenoxide elimination of the initially cyclized product and generated other electrophilic selenium species that continued the cyclization process (eq 23). 35 In a reaction reminiscent of eq 14, the cyclization of an unsaturated enol acetate was effected with NPSP in the presence of tin tetrachloride (eq 24). 36 The cyclization of tryptophan derivatives to the corresponding pyrroloindoles was reported simultaneously by two groups.…”

Section: %mentioning

confidence: 99%