73739-28-3Relevant academic research and scientific papers
Aromatic aldols and 1,5-diketones as optimized fragrance photocages
Griesbeck, Axel G.,Hinze, Olga,Goerner, Helmut,Huchel, Ursula,Kropf, Christian,Sundermeier, Uta,Gerke, Thomas
experimental part, p. 587 - 592 (2012/06/30)
Aromatic aldols and 1,5-diketones with abstractable γ-hydrogen atoms are highly photoactive cage molecules for the release of fragrance carbonyl compounds (aldehydes and Michael ketones, respectively). Aldols 3a-d are easily accessible by Mukaiyama addition and are cleaved to form the substrates with high quantum yields under solar radiation. By tuning the properties of the chromophores, a series of δ-damascone cages 5 were developed that can be used for selective and fast (5a,e) or slow (5b,d) release of fragrances under air and solar irradiation. The intermediates of the Norrish II process were observed by laser transient absorption spectroscopy.
From allylic alcohols to aldols through a new nickel-mediated tandem reaction: Synthetic and mechanistic studies
Cuperly, David,Petrignet, Julien,Crevisy, Christophe,Gree, Rene
, p. 3261 - 3274 (2008/09/18)
Nickel hydride type complexes have been successfully developed as catalysts for the tandem isomerization-aldolization reaction of allylic alcohols with aldehydes. Optimization of the reaction conditions has shown that a cocatalyst, such as MgBr2, has a very positive effect on the kinetics of the reaction and in the yields of aldols. Under such optimized conditions {[NiHCl(dppe)] + MgBr2 at 3-5 mol %)}, this reaction affords the aldols in good to excellent yields. It is a full-atom-economy-type reaction that occurs under mild conditions. Furthermore, it has a broad scope for the allylic alcohols and it is compatible with a wide range of aldehydes, including very bulky derivatives. The reaction is completely regioselective, but it exhibits a low stereoselectivity, except for allylic alcohols with a bulky substituent at the carbinol center. The use of chiral non-racemic catalysts was not successful, affording only racemic compounds. However, it was possible to use asymmetric synthesis for the preparation of optically active aldols. Various mechanistic studies have been performed using, for instance, a deuterated alcohol or a deuterated catalyst. They gave strong support to a mechanism involving first a transition-metal-mediated isomerization of the allylic alcohol into the free enol, followed by the addition of the latter intermediate onto the aldehyde in an "hydroxyl-carbonyl-ene" type reaction. These results confirm that allylic alcohols can be considered as new and useful partners in the development of the aldol reaction.
Stereoselective crossed aldol reaction via boron enolates generated from α-iodo ketones and 9-borabicyclo[3.3.1]nonane
Mukaiyama, Teruaki,Takuwa, Tomofumi,Yamane, Keiko,Imachi, Shouhei
, p. 813 - 823 (2007/10/03)
Boron enolates were in situ-generated reductively by treating various α-iodo ketones such as 2-iodo-1-phenylpropan-1-one, 2-iodo-1-(4-methoxyphenyl)propan-1-one, 2-iodopentan-3-one, 2-iodo-2-methyl-1-phenylpropan-1-one, 3,4-dihydro-2-iodo-1(2H)-naphthalenone, 2-iodo-1-phenylethan-1-one and 1-iodo-4-phenylbutan-2-one with 9-borabicyclo[3.3.1]nonane (9-BBN). Aldols were produced in good yields with good to high diastereoselectivities by subsequent reaction of boron enolates thus formed with various aldehydes. Several boron enolates derived from α-iodo ketones and pinacolatoborane were successfully isolated by distillation, though the yields were rather moderate.
Stereoselective crossed aldol reaction via boron enolate generated from α-iodoketones and 9-BBN-H
Mukaiyama, Teruaki,Imachi, Shouhei,Yamane, Keiko,Mizuta, Masahiro
, p. 698 - 699 (2007/10/03)
Boron enolates were in situ generated smoothly by treating α-iodo ketones with 9-BBN-H, and aldols were produced in highly diastereoselective manner by successive reaction with various aldehydes at low temperature.
Boron-mediated aldol reaction of carboxylic esters: Complementary anti- and syn-selective asymmetric aldol reactions
Inoue, Tadashi,Liu, Ji-Feng,Buske, Dana C.,Abiko, Atsushi
, p. 5250 - 5256 (2007/10/03)
The boron-mediated aldol reaction of carboxylic esters is described in detail. Contrary to the general belief that carboxylic esters are inert under the condition of the boron enolate formation, propionate esters are enolized with certain combinations of a boron triflate and an amine. More importantly, the stereochemical course of the aldol reaction can be controlled by the judicious selection of the enolization reagents. Treatment of propionate esters with c-Hex2BOTf and triethylamine produces anti-aldol products, and that with Bu2BOTf and diisopropylethylamine gives syn-aldol products selectively after reaction with aldehydes. Complementary anti- and syn-selective asymmetric aldol reactions with structurally related, readily available chiral norephedrine-derived propionate esters are developed.
Direct, practical, and powerful crossed aldol additions between ketones and ketones or aldehydes utilizing environmentally benign TiCl4-Bu3N reagent
Tanabe, Yoo,Matsumoto, Noriaki,Higashi, Takahiro,Misaki, Tomonori,Itoh, Tomotaka,Yamamoto, Misako,Mitarai, Kumi,Nishii, Yoshinori
, p. 8269 - 8280 (2007/10/03)
An efficient TiCl4-Bu3N - (cat. TMSCl)-promoted aldol addition between ketones and ketones or aldehydes was performed. This environmentally benign method is advantageous from a green chemical viewpoint with regard to yield, substrate
Phosphine/Lewis acid mediated Reformatsky-type reaction of α-bromoketone or -thioester derivatives
Hashimoto, Yukihiko,Kikuchi, Satoshi
, p. 126 - 127 (2007/10/03)
The combination of (?-tolyl)3P/TiCl4 effectively promoted the Reformatsky-type reaction of α-bromoketone or -thioester derivatives with various aldehydes, and the corresponding β-hydroxy carbonyl compounds were obtained in good yield
Scope and limitations of chiral B-[3,5-bis(trifluoromethyl)phenyl]oxazaborolidine catalyst for use in the Mukaiyama aldol reaction
Ishihara,Kondo,Yamamoto
, p. 9125 - 9128 (2007/10/03)
A new chiral oxazaborolidine catalyst was prepared in situ from 3,5-bis(trifluoromethyl)phenylboron dichloride and N-(p-toluenesulfonyl)-(S)-tryptophan. This catalyst is much more active than Corey's original catalyst for the Mukaiyama aldol reaction of a
Simple metal alkoxides as effective catalysts for the hetero-aldol-Tishchenko reaction
Mascarenhas, Cheryl M.,Duffey, Matthew O.,Liu, Shih-Yuan,Morken, James P.
, p. 1427 - 1429 (2008/02/09)
(equation presented) This paper reports the utility of simple metal alkoxides for the catalytic, stereoselective hetero-aldol-Tishchenko reaction (eq 1). Choice of metal alkoxide is crucial to achieving high efficiency and stereoselectivity. Whereas NaO-t
Diastereoselective aldol reaction of α-bromo ketones with aliphatic aldehydes by using titanium(II) chloride and copper
Mukaiyama, Teruaki,Kagayama, Akifumi,Igarashi, Koji,Shiina, Isamu
, p. 1157 - 1158 (2007/10/03)
Highly diastereoselective aldol reaction of α-bromo ketones with aliphatic aldehydes was successfully carried out by using titanium(II) chloride and copper in dichloromethane at low temperature. Similarly, Reformatsky-type reaction of α-bromo thioester with aliphatic aldehydes was promoted under mild conditions to afford β-hydroxy thioesters in good to moderate yields.
