124094-56-0Relevant academic research and scientific papers
Highly diastereo- and enantioselective direct aldol reactions of aldehydes and ketones catalyzed by siloxyproline in the presence of water
Aratake, Seiji,Itoh, Takahiko,Okano, Tsubasa,Nagae, Norio,Sumiya, Tatsunobu,Shoji, Mitsuru,Hayashi, Yujiro
, p. 10246 - 10256 (2008/09/18)
Proline-based organocatalysts have been developed for a highly enantioselective, direct aldol reaction of aldehydes and ketones in the presence of water. While several surfactant-proline combined catalysts have proved effective, proline derivatives with a hydrophobic moiety such as rraw-siloxy-L-proline and cis-siloxy-D-proline, both of which are easily prepared from the same commercially available 4-hydroxy-L-proline. have been found to be the most effective organocatalysts examined in this study, affording the aldol product with excellent diastereo- and enantioselectivities, these two catalysts generating opposite enantiomers. Water affects the selectivity, and poor results are obtained under neat reaction conditions or in dry organic solvents. More than three equivalents of water are required for the best diastereo- and enantioselectivities. while three equivalents is the recommended amount from a synthetic point of view. The reaction proceeds in the organic phase, and also proceeds in the presence of a large amount of water. The large-scale preparation of aldols with the minimal use of an organic solvent, including in the purification step. is described.
Crossed Aldol Type Condensation Reactions in Aqueous Media
Chan, T. H.,Li, C. J.,Wei, Z. Y.
, p. 505 - 507 (2007/10/02)
Directed crossed aldol type condensations can be carried out in aqueous media using α-halocarbonyl compounds, aldehydes, and metallic zinc or tin.
β-Hydroxy Ketones from the Iodine-catalysed Reaction of α-Bromo Ketone with Aldehydes Mediated by Trialkylstibine
Huang, Yao-Zeng,Chen, Chen,Shen, Yanchang
, p. 2855 - 2860 (2007/10/02)
β-Hydroxy ketones can be synthesized in excellent yield by the iodine-catalysed reaction of α-bromo ketones with various aldehydes mediated by trialkylstibine.
Reaction of α-Halogeno Ketones with Carbonyl Compounds Promoted by CeI3, CeCl3-NaI,or CeCl3-SnCl2
Fukuzawa, Shin-ichi,Tsuruta, Takuya,Fujinami, Tatsuo,Sakai, Shizuyoshi
, p. 1473 - 1478 (2007/10/02)
Reaction of α-halogeno ketones with aldehydes in the presence of CeI3 in tetrahydrofuran is found to give α,β-unsaturated ketones in excellent yields under mild conditions.In contrast, treatment of α-halogeno ketones and carbonyl compounds with CeCl3-NaI or CeCl3-SnCl2 affords β-hydroxy ketones in good yields.It is assumed that these reactions proceed via cerium enolates.The combined reagents, however, cannot be applied to a Reformatsky-type reaction.Regiospecific and aldehyde chemoselective aldol synthesis are also described.
Regio- and Stereocontrolled Synthesis of Allenic and Acetylenic Derivatives. Organotitanium and Boron Reagents
Furuta, Kyoji,Ishiguro, Masaharu,Haruta, Ryuichi,Ikeda, Nobuo,Yamamoto, Hisashi
, p. 2768 - 2776 (2007/10/02)
The propargyltitanium reagents derived from 1-alkylpropyne condensed with aldehydes to give α-allenyl alcohol regioselectively, while the allenyltitanium reagents generated from 1-alkyl-1-butyne derivatives gave threo-β-acetylenic alcohols with high regio- and stereoselectivities.The course of the reaction was determined by the substitution pattern of starting alkynes.The similar reactions of metallated 1,3-bis(trialkylsilyl)propyne or (trialkylsilyl)acetonitrile with aldehydes were also investigated.
