- Solid-support synthesis of 1,2-diols and γ-lactones through addition of α-(benzoyloxy)crotylindium reagents to aldehydes
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A procedure for the solid phase synthesis of 1,2-diols and γ-lactones from α-(hydroxy)crotylstannane has been developed through transmetalation with InBr3. A variety of 1,2-diols and γ-lactones were synthesized in satisfactory yields and, in some cases, with excellent diastereoselectivity. The products are formed free of tin contamination.
- Cossy, Janine,Rasamison, Chrystelle,Pardo, Domingo Gomez,Marshall, James A.
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p. 629 - 633
(2007/10/03)
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- Substrate-directed diastereoselective hydroformylations, 1: Substrate-directed diastereoselective hydroformylation of methallylic alcohols - Development of an efficient catalyst-directing group for rhodium-catalyzed hydroformylation
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The development of an efficient catalyst-directing group based on ortho-diphenylphosphanyl benzoate (o-DPPB) for the substrate-directed, diastereoselective hydroformylation of methallylic alcohols 5 is described. The hydroformylation of methallylic o-DPPB esters 9 provides the corresponding syn-aldehydes 10 with diastereoselectivities of up to 96:4. A specific steric demand of the substituent at the stereogenic center of the methallylic derivatives 9 was found to be necessary to achieve a high degree of stereoselectivity. Experiments have been performed that prove that the o-DPPB group acts as a catalyst-directing group by reversibly coordinating to the catalyst. The removal of the o-DPPB group was accomplished by means of alkaline hydrolysis, thereby furnishing the lactols 6. Oxidation of 6 provides the corresponding γ-lactones 7. VCH Verlagsgesellschaft mbH, 1997.
- Breit, Bernhard
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p. 1841 - 1851
(2007/10/03)
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- Stereoselective Thermal Reactions between (E)-1-Alkoxymethoxybut-2-enyl(tributyl)stannanes and Aldehydes
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(E)-1-Methoxymethoxybut-2-enyl(tributyl)stannane (6), readily available by the addition of tributylstannyl-lithium to crotonaldehyde and alkylation of the adduct using chloromethyl methyl ether, reacts on heating with aldehydes to give anti-4-hydroxy-3-methyl-cis-1,2-enol ethers.These on hydrolysis and oxidation provide trans-4,5-disubstituted butyrolactones.
- Pratt, Andrew J.,Thomas, Eric J.
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p. 1521 - 1527
(2007/10/02)
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- Synthesis of Optically Active (E)-1-Alkoxymethoxybut-2-enyl(tributyl)stannanes: Stereochemistry of their Thermal Reactions with Aldehydes
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(1R)- and (1S)-1--(E)-but-2-enyl(tributyl)stannanes (8) and (9), whose configurations were assigned by correlation with (2R)- and (2S)-pentan-2-ol (14) and (15), react stereoselectively on heating with benzaldehyde to give (3S,4S)- and (3R,4R)-4-hydroxy-3-methyl-(Z)-1,2-enol ethers (16) and (18), respectively, the configurations of these products being established by correlation with pseudoephedrine.
- Jephcote, Vincent J.,Pratt, Andrew J.,Thomas, Eric J.
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p. 1529 - 1535
(2007/10/02)
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- SYNTHESE DE COMPOSES DIHYDRO-2,3 FURANNIQUES PAR HYDROBORATION D'ALCOOLS β-ACETYLENIQUES
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Hydroboration of β acetylenic alcohols followed by NaOH/H2O2 oxidation leads to hemiacetals of γ aldols which are easily dehydrated to 2,3-dihydrofuran compounds.The reaction gives good yields with hindered alcohols and its stereochemistry may be controlled during the organometallic synthesis of the starting alcohol.
- Dana, Gilbert,Figadere, Bruno,Touboul, Estera
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p. 5683 - 5684
(2007/10/02)
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- On The Use of E-1-Methoxymethoxybut-2-enyl(tri-n-butyl)stannane as a threo-Selective, Homo-enolate Equivalent
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(E)-1-Methoxymethoxybut-2-enyl(tri-n-butyl)stannane, readily available by addition of tri-n-butylstannyl-lithium to crotonaldehyde, and protection of the alcohol so formed using chloromethyl methyl ether, reacts on heating with aromatic and aliphatic aldehydes to give threo-4-hydroxy-3-methyl-cis-1,2-enol ethers, hydrolysis and oxidation of which provides a stereoselective route to trans-4,5-disubstituted butyrolactones.
- Pratt, Andrew J.,Thomas, Eric J.
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p. 1115 - 1117
(2007/10/02)
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