- Bismuth compounds in organic synthesis. A one-pot synthesis of homoallyl ethers and homoallyl acetates from aldehydes catalyzed by bismuth triflate
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(Chemical Equation Presented) Three one-pot methods for the conversion of aldehydes to homoallyl ethers catalyzed by Bi(OTf)3? xH 2O (1 x 4) have been developed. The one-pot synthesis of homoallyl ethers can be achieved either by
- Anzalone, Peter W.,Baru, Ashvin R.,Danielson, Eric M.,Hayes, Patrick D.,Nguyen, Mai P.,Panico, Ambrose F.,Smith, Russell C.,Mohan, Ram S.
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p. 2091 - 2096
(2007/10/03)
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- Trimethylsilyl trifluoromethanesulfonate catalyzed one-pot method for the conversion of aldehydes to homoallyl ethers in an ionic liquid
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A mild method for the trimethylsilyl trifluoromethanesulfonate (TMSOTf) catalyzed one-pot synthesis of homoallyl ethers from aldehydes has been developed in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim] [OTf]). The advanta
- Anzalone, Peter W.,Mohan, Ram S.
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p. 2661 - 2663
(2007/10/03)
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- Scope of alkoxymethyl radical cyclizations
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We have explored different aspects of the cyclization capability of alkoxymethyl radicals and report here a full account of our investigations. The required radicals were generated from (phenylseleno)-methyl ethers (e.g., 6), which were prepared from homoallylic or bis-homoallylic alcohols by a two-step process. The alcohols were alkylated with (iodomethyl)tributylstannane. The stannanes were reacted with n-BuLi, and the resulting α-alkoxyanions were trapped with diphenyldiselenide to give the (phenylseleno)methyl ethers, which were stable to chromatography. When treated with tributyltin hydride, in the presence of a radical initiator, these precursors undergo a smooth cyclization to substituted tetrahydrofurans and tetrahydropyrans. Formation of the cyclization product was found to be the primary pathway even at relatively high tin hydride concentration. The diastereoselectivity of this cyclization was comparable to that observed in other radical cyclizations. The cis selectivity in cyclization of 6 increased gradually (up to 11:1) as the reaction temperature was lowered. The cyclization can be used for the synthesis of bicyclic and tricyclic compounds and can be incorporated in systems capable of tandem cyclizations.
- Rawal,Singh,Dufour,Michoud
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p. 7718 - 7727
(2007/10/02)
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- Homogeneous Catalysis. Use of the Catalyst for the Sakurai Reaction of Allylic Silanes with Orthoesters, Acetals, Ketals and Carbonyl Compounds.
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The effectiveness of the catalyst for the Sakurai reaction has been explored for a variety of allylic silanes reacting with orthoesters, acetals, ketals, aldehydes and ketones. Key Words: Sakurai reaction, titanium based catalyst.
- Hollis, T. Keith,Robinson, N. P.,Whelan, John,Bosnich, B.
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p. 4309 - 4312
(2007/10/02)
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- Cyclization of Alkoxymethyl Radicals
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Alkoxymethyl radicals, generated conveniently from phenylseleno precursors, cyclize to afford substituted tetrahydrofurans and tetrahydropyrans in excellent yield and with good stereoselectivity.
- Rawal, Viresh H.,Singh, Surendra P.,Dufour, Claire,Michoud, Christophe
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p. 5245 - 5247
(2007/10/02)
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- STEREOSELECTIVE SYNTHESIS OF 3-(D-GLYCOPYRANOSYL)PROPENES BY USE OF ALLYLSILANES
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Reactions of allylsilanes with methyl pyranosides and pyranosyl chlorides proceeded very smoothly in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate and iodosilane to give the corresponding glycopyranosyl-3-propenes in highly stereoselective mode.The configuration depends upon the structure of allylsilanes. 2-Bromo-2-propenyltrimethylsilane, the lowest nucleophile among the allylsilanes used, afforded an almost pure C-α-glycosyl compound.
- Hosomi, Akira,Sakata, Yasuyuki,Sakurai, Hideki
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p. 223 - 232
(2007/10/02)
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- REGIOSPECIFIC ALLYLATION OF ACETALS WITH ALLYLSILANES CATALYZED BY IODOTRIMETHYLSILANE. SYNTHESIS OF HOMOALLYLETHERS
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Allylation of acetals with allylsilanes is catalyzed by iodotrimethylsilane to give the corresponding homoallyl ethers, with regiospecific transposition of the allyl group.
- Sakurai, Hideki,Sasaki, Koshi,Hosomi, Akira
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p. 745 - 748
(2007/10/02)
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