105401-07-8Relevant academic research and scientific papers
Aldol reactions on solid phase. Sc(OTf)3-catalyzed aldol reactions of polymer-supported silyl enol ethers with aldehydes providing convenient methods for the preparation of 1,3-diol, β-hydroxy carboxylic acid, and β-hydroxy aldehyde libraries
Kobayashi, Shu,Hachiya, Iwao,Yasuda, Masaru
, p. 5569 - 5572 (1996)
Aldol reactions on solid phase have been achieved. In the presence of a catalytic amount of scandium triflate (Sc(OTf)3), polymer-supported silyl enol ethers reacted with aldehydes to afford the corresponding β-hydroxy thioester derivatives, which were reduced to 1,3-diol and β-hydroxy aldehyde derivatives, or hydrolyzed to β-hydroxy carboxylic acid derivatives.
Catalytic Asymmetric Iterative/Domino Aldehyde Cross-Aldol Reactions for the Rapid and Flexible Synthesis of 1,3-Polyols
Lin, Luqing,Yamamoto, Kumiko,Mitsunuma, Harunobu,Kanzaki, Yamato,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 15418 - 15421 (2015/12/26)
We report here catalytic asymmetric iterative and domino cross-aldol reactions between aldehydes, endowed with a high level of robustness, flexibility, and generality. A Cu(I)-DTBM-SEGPHOS complex catalyzes an asymmetric cross-aldol reaction between acceptor aldehydes and boron enolates derived from donor aldehydes, which are generated through Ir-catalyzed isomerization of allyloxyboronates. The unit process can be repeated using the aldol products in turn as acceptor substrates for the subsequent asymmetric aldol reaction. The donor aldehydes and stereoselectivity can be flexibly switched in a stepwise manner for the double-aldol reaction. Furthermore, asymmetric triple- and quadruple-aldol reactions are possible in one-pot using the appropriate amounts of donors and amine additives, rapidly elongating the carbon skeleton with controlling up to eight stereocenters. The method should be useful for straightforward synthesis of enantiomerically and diastereomerically enriched 1,3-polyols.
Rapid and stereochemically flexible synthesis of polypropionates: Super-silyl-governed aldol cascades
Brady, Patrick B.,Yamamoto, Hisashi
, p. 1942 - 1946 (2012/04/04)
Polypropionates made EZ: The E/Z geometry of tris(trimethylsilyl)silyl super silyl enol ethers derived from propionaldehyde controls diastereoselectivity in the aldehyde crossed-aldol reaction. These silyl enol ethers can participate in polyaldol cascade reactions, thus allowing the one-pot synthesis of four different dipropionate stereotetrads (see scheme), and polyketides bearing up to five contiguous stereocenters.
Combined proline-surfactant organocatalyst for the highly diastereo- and enantioselective aqueous direct cross-aldol reaction of aldehydes
Hayashi, Yujiro,Aratake, Seiji,Okano, Tsubasa,Takahashi, Junichi,Sumiya, Tatsunobu,Shoji, Mitsuru
, p. 5527 - 5529 (2007/10/03)
(Chemical Equation Presented) Why not combine the two? The asymmetric direct aldol reaction of two different aldehydes was catalyzed by a combined proline-surfactant organic catalyst in the presence of water. A stable emulsion was formed in the reaction mixture, and the aldols were obtained with excellent diastereo- and enantioselectivities (see scheme).
Highly diastereoselective anti-Aldol reactions utilizing the titanium enolate of cis-2-arylsulfonamido-1-acenaphthenyl propionate
Ghosh, Arun K.,Kim, Jae-Hun
, p. 1063 - 1066 (2007/10/03)
(Matrix presented) anti-Aldol reaction of Ti-enolate derived from cis-2-arylsulfonamido-1-acenaphthenyl propionate with representative aldehydes proceeded in excellent yield with high diastereoselectivity. Both enantiomers of cis-2-amino-1-acenaphthenol w
Highly diastereofacial anti-aldol reaction: Practical synthesis of optically active anti-2-alkyl-3-hydroxycarboxylic acid ester units
Kurosu,Lorca
, p. 1205 - 1209 (2007/10/03)
A variety of esters derived from commercially available norephedrine were used in diastereoselective anti-aldol reactions. The aldol reaction of designed 2-(N-2-methylbenzyl-N-2,4,6-trimethylbenzyl)-amino-1-phenylpropanol esters 4a-d with aldehydes furnished anti-2-alkyl-3-hydroxycarboxylic acid esters in excellent diastereomeric ratios (>98:2) when LDA-Cp2ZrCl2 (0.3 equiv) was used for enolization, followed by transmetalation into the zirconium enolate for aldolization. The novel auxiliary 3 for the anti-aldol reaction does not exhibit the ordinary basicity of tertiary amines; 3 can be extracted from acidic media with organic solvents. Its use is, therefore, very advantageous not only for extraction of the aldol products from the acidic water solutions; but also for recovering the chiral auxiliary 3 after the reductive cleavage. Treatment of aldol or 3-protected aldol products with DIBAL-H or LiAIH4 affords the versatile synthons, 2-alkyl-propane-1,3-diols or those 3-protected diols in >98% ee's together with 3 in nearly quantitative recovery.
BCl3- and TiCl4-mediated reductions of β-hydroxy ketones
Sarko, Christopher R.,Collibee, Scott E.,Knorr, Allison L.,DiMare, Marcello
, p. 868 - 873 (2007/10/03)
Syn-selective reduction protocols for β-hydroxy ketones are described exploiting the intermediacy of titanium and boron chelates derived from TiCl4 and BCl3, respectively. Reductions are conducted at -78°C in CH2Cl2/
Stereoselective Acetalization of 1,3-Alkanediols by l-Menthone: Application to the Resolution of Racemic 1,3-Alkanediols and to the Determination of the Absolute Configuration of Enantiomeric 1,3-Alkanediols
Harada, Toshiro,Kurokawa, Hideaki,Kagamihara, Yasuhiro,Tanaka, Sachi,Inoue, Atsushi,Oku, Akira
, p. 1412 - 1421 (2007/10/02)
A general and reliable method for the resolution of racemic 1,3-alkanediols, which involves their conversion into diastereomeric spiroacetals derived from l-menthone, is described.Thus, the reaction of the bis-O-trimethylsilyl derivatives of racemic 1,3-alkanediols with l-menthone in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate affords the diastereomeric spiroacetals 3 and 4.The two can be readily separated by silica gel column chromatography.Hydrolysis of each diastereomer under acidic conditions liberates the corresponding enantiomerically pure diol.An empirically derived correlation of configuration and 1H NMR chemical shifts for spiroacetals 3 and 4 has been developed which is rationalized based on long-range effects due to the magnetic anisotropy inherent to the menthane ring in a rigid spiroacetal conformation.The method described here should be widely applicable to the determination of the absolute configuration of various 1,3-alkanediols.
Enantioselective acetalization of racemic 1,3-alkanediols with l-methone under kinetically controlled conditions
Harada, Toshiro,Tanaka, Sachi,Oku, Akira
, p. 8621 - 8630 (2007/10/02)
Racemic 1,3-alkanediols (rac-1) undergo an enantioselective acetalization by treatment with l-methone enol trimethylsilyl ether (10) in the presence of trifluoromethanesulfonic acid (10 mol%) to give thermodynamically less stable spiroacetal 3 (derived fr
Asymmetric synthesis using diisopropyl tartrate modified (E)- and (Z)-crotylboronates: Preparation of the chiral crotylboronates and reactions with achiral aldehydes
Roush, William R.,Ando, Kaori,Powers, Daniel B.,Palkowitz, Alan D.,Halterman, Ronald L.
, p. 6339 - 6348 (2007/10/02)
Diisopropyl tartrate modified (E)- and (Z)-crotylboronates 2 and 3 are easily prepared with very high isomeric purity (≥98% E for 2; ≥99% Z for 3) via the metalation of (E)- and (Z)-2-butene with n-BuLi and KOtBu in THF followed by treatment of the (E)- a
