71699-31-5Relevant academic research and scientific papers
Aldol addition of aldehydes - A stereoselective approach to syn-3-hydroxyaldehydes
Mahrwald, Rainer,Costisella, Burkhard,Guendogan, Bilgi
, p. 4543 - 4544 (1997)
TiCl4-aldehyde complexes undergo aldol addition with enolizable aldehydes in the presence of base. The expected 3-hydroxyaldehydes were obtained with a high degree of syn-selectivity.
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.
Rh-catalyzed aldehyde - Aldehyde cross-aldol reaction under base-free conditions: In situ aldehyde-derived enolate formation through orthogonal activation
Lin, Luqing,Yamamoto, Kumiko,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 2974 - 2983 (2014/01/06)
The chemoselective generation of aldehyde-derived enolates to realize an aldehyde - aldehyde cross-aldol reaction is described. A combined Rh/dippf system efficiently promoted the isomerization/aldol sequence by using primary allylic, homoallylic, and bishomoallylic alcohols; secondary allylic and homoallylic alcohols; and trialkoxyboranes that were derived from primary allylic and homoallylic alcohols. The reaction proceeded at ambient temperature under base-free conditions, thus giving cross-aldol products with high chemoselectivity. Mechanistic studies, as well as its application to double-aldol processes under protecting-group-free conditions, are also described. Copyright
Rhodium-catalyzed cross-aldol reaction: In situ aldehyde-enolate formation from allyloxyboranes and primary allylic alcohols
Lin, Luqing,Yamamoto, Kumiko,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 10275 - 10279,5 (2012/12/12)
Dip in. A Rh/dippf catalyst generates aldehyde-derived enol boranes at ambient temperature by isomerization of allyloxy- and homoallyloxyboranes. A one-pot isomerization/cross-aldol sequence provides aldehyde-aldehyde adducts in good yield with syn select
Rhodium-catalyzed cross-aldol reaction: In situ aldehyde-enolate formation from allyloxyboranes and primary allylic alcohols
Lin, Luqing,Yamamoto, Kumiko,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 10275 - 10279 (2013/01/15)
Dip in! A Rh/dippf catalyst generates aldehyde-derived enol boranes at ambient temperature by isomerization of allyloxy- and homoallyloxyboranes. A one-pot isomerization/cross-aldol sequence provides aldehyde-aldehyde adducts in good yield with syn select
Catalytic enantioselective 1,2-diboration of 1,3-dienes: Versatile reagents for stereoselective allylation
Kliman, Laura T.,Mlynarski, Scott N.,Ferris, Grace E.,Morken, James P.
, p. 521 - 524 (2012/03/11)
More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. Copyright
DIRECT, ENANTIOSELECTIVE ALDOL COUPLING OF ALDEHYDES USING CHIRAL ORGANIC CATALYSTS
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Page/Page column 23; 26-27, (2008/06/13)
Nonmetallic, chiral organic catalysts are used to catalyze an enantioselective aldol coupling reaction between aldehyde substrates. The reaction may be carried out with a single enolizable aldehyde, resulting in dimerization to give a β-hydroxy aldehyde,
Stereocontrol in aldol addition - Synthesis of syn and anti 3-Hydroxy aldehydes
Mahrwald,Costisella,Gündogan
, p. 262 - 264 (2007/10/03)
syn 3-Hydroxy aldehydes were obtained with a high level of stereoselectivity by aldol addition in the presence of TiCl4. The corresponding anti 3-hydroxy aldehydes were obtained by thermodynamic equilibration in the presence of titanium(IV) alkoxides.
Acyclic Stereoselection. 7. Stereoselective Synthesis of 2-Alkyl-3-hydroxy Carbonyl Compounds by Aldol Condensation
Heathcock, Clayton H.,Buse, Charles T.,Kleschick, William A.,Pirrung, Michael C.,Sohn, John E.,Lampe, John
, p. 1066 - 1081 (2007/10/02)
The stereochemistry of the aldol condensation of preformed lithium enolates of a variety of ethyl ketones and propionic acid derivatives with aldehydes has been investigated.It is found that certain compounds give completely or nearly completely one diastereomeric enolate and that the stereostructure of the resulting aldol is correlated with the stereostructure of the enolate from which is formed.The observed stereochemistry may be understood in terms of an ordered transition state in which both oxygens are oriented in more or less the same direction.It is shown that the observed stereochemistry is kinetically controlled.In many cases, the initial aldol adduct equilibrates to furnish predominantly a threo isomer.The rate of equilibration varies widely, ranging from very fast at -60 deg C with the propiophenone-benzaldehyde adduct to slow at 25 deg C for the ethyl tert-butyl ketone-benzaldehyde adduct.The equilibration behavior of lithium ketolates is compared with that of zinc ketolates, and some differences are noted.A method for achieving erythro-threo equilibration via a chloral hemiacetal is presented.A new reagent is introduced (trimethylsilyloxy ketone 36) which may be used to stereoselectively homologate an aldehyde to an erythro α-methyl-β-hydroxy acid.As an application of the use of stereoselective aldol condensations in synthesis, (+/-)-ephedrine (48) has been synthesized from benzaldehyde in 71 percent overall yield.
