97949-92-3Relevant academic research and scientific papers
Highly diastereoselective acetal cleavages using novel reagents prepared from organoaluminum and pentafluorophenol
Ishihara, Kazuaki,Hanaki, Naoyuki,Yamamoto, Hisashi
, p. 10695 - 10704 (2007/10/02)
Chiral acetals derived from aldehydes and (-)-(2R,4R)-2,4-pentanediol are cleaved selectively by organoaluminum reagents. The reaction proceeds via the retentive-alkylation process with >95% selectivities in most cases. Trialkylaluminum reagent is utilized for higher alkyl transfers, but for smaller alkyl transfers, a new reagent system, combining trialkylaluminum and the halophenols such as pentafluorophenol and 2,4,6-trichlorophenol, is employed. Chiral acetals derived from aldehydes and 1,3-butanediol are cleaved selectively by trialkylaluminum, even for smaller alkyl transfers. Oxetane is also exposed to these aluminum reagents, and the retentive-alkylation products are obtained stereoselectively. The reaction of acetals derived from (-)-(2R,4R)-2,4-pentanediol and ketones in the presence of a catalytic amount of aluminum pentafluorophenoxide produces reductively cleaved products with high diastereoselectivity. The reaction is a new means of diastereoselective cleavage of acetals: an intramolecular Meerwein-Ponndorf-Verley reductive and Oppenauer oxidative reaction on an acetal template.
Nucleophilic cleavage of acetals using organometallic reagents
Mori, Atsunori,Fujiwara, Junya,Maruoka, Keiji,Yamamoto, Hisashi
, p. 83 - 94 (2007/10/02)
A highly chemo- and stereo-selective cleavage of acetals derived from (-)(2R,4R)-2,4-pentanediol with organoaluminum and organotitanium reagents has been demonstrated. The reactions proceed under mild conditions with excellent yields and high chemoselectivities to give, after removal of the auxiliary, chiral alcohols of high enantiomeric purities.
ASYMMETRIC SYNTHESIS via CHIRAL ACETAL TEMPLATES. 8. REACTIONS WITH ORGANOMETALLIC REAGENTS
Lindell, Stephen D.,Elliott, John D.,Johnson, William S.
, p. 3947 - 3950 (2007/10/02)
The titanium tetrachloride catalyzed coupling of organometallic reagents with chiral acetals 1 is shown to provide a convenient route for the preparation of a variety of chiral alcohols 4 of high optical purity.
NUCLEOPHILIC CLEAVAGES OF ACETALS USING ORGANOTITANIUM REAGENTS. A NEW SYNTHESIS OF CHIRAL ALCOHOLS
Mori, Atsunori,Maruoka, Keiji,Yamamoto, Hisashi
, p. 4421 - 4424 (2007/10/02)
A highly chemo- and stereoselective cleavage of acetals derived from (-)-(2R, 4R)-2,4-pentanediol with organotitanium reagents has been demonstrated.The reraction proceeds under mild condations in excellent yield and high chemoselectivity to give, after removel of auxiliary, the chiral alcohols of high enantiopurities.In addition, complexation of chiral acetals and TiCl4 followed by treatment with n-butyllithium also results in formation of the corresponding n-butylated alcohols with high stereoselectivity.
