71699-34-8Relevant academic research and scientific papers
Titanium and Boron Mediated Aldol Reactions of β-Hydroxy Ketones
Luke, George P.,Morris, Joel
, p. 3013 - 3019 (1995)
The reaction of enolates derived from titanium and boron complexes of β-hydroxy ketones with aldehydes afforded aldol products in good to excellent yields.Whereas the boron mediated reactions gave exclusively anti aldol products derived from the reaction at Cα, the titanium mediated reactions produced primarily syn aldol products from reaction at Cα'.The product selectivites observed in the titanium mediated aldol reactions were highly dependent on the substitution pattern of the starting β-hydroxy ketone.
Lithium hexamethyldisilazide-mediated enolizations: Influence of triethylamine on E/Z selectivities and enolate reactivities
Godenschwager, Peter F.,Collum, David B.
supporting information; experimental part, p. 8726 - 8732 (2009/02/02)
Lithium hexamethyldisilazide (LiHMDS) in triethylamine (Et 3N)/toluene is shown to enolize acyclic ketones and esters rapidly and with high E/Z selectivity. Mechanistic studies reveal a dimer-based mechanism consistent with previous studies of
Stereoselective synthesis of a novel spiroacetal-dihydropyrone related to auripyrone
Perkins, Michael V.,Jahangiri, Saba,Taylor, Max R.
, p. 2025 - 2028 (2007/10/03)
A model spiroacetal-dihydropyrone related to that found in auripyrones A and B has been synthesised by a spiroacetalisation dehydration cascade. The route includes an unusual mutual kinetic diastereoselecting aldol reaction combining the key fragments.
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.
Stereoselective aldol reaction of α-seleno carbonyl compounds: Preparation of (Z)-α,β-unsaturated carbonyl compounds
Nakamura, Shuichi,Hayakawa, Toshinobu,Nishi, Tatsuya,Watanabe, Yoshihiko,Toru, Takeshi
, p. 6703 - 6711 (2007/10/03)
The aldol reaction of the titanium enolates of α-seleno esters in the presence of Ph3P or Ph3PO gave the products with high stereoselectivity favoring the syn isomers. Reaction of α-seleno ketones with TiCl4 in the presence of 2 equiv. of Et3N, and subsequently with aldehydes, gave the aldol products with high syn selectivity. The stereoselectivity in the aldol reaction of 3-pentanone also increased by using an excess amount of Et3N. The aldol products thus obtained from the α-seleno carbonyl compounds could be stereospecifically converted to (Z)-α,β-unsaturated carbonyl compounds by treatment with pyridine. (Z)-Alkylidenecyclopentanones were exclusively formed by treatment of the syn-aldol products with Et3N in the dark.
Diastereoselective aldol and reformatsky reactions of α-halo carbonyl compounds and aldehydes mediated by Titanium(II) Chloride
Kagayama,Igarashi,Shiina,Mukaiyama
, p. 2579 - 2585 (2007/10/03)
Highly diastereoselective aldol reactions of α-bromo ketones with several aldehydes were successfully carried out by using a combination of titanium(II) chloride and copper or sodium iodide in dichloromethane-pivalonitrile at low temperature. Similarly, Reformatsky reactions of α-bromo thioester with aliphatic aldehydes proceeded to afford β-hydroxy thioesters in good yields under mild conditions.
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
Formation of (Z) Dialkylboron Enolates from Enolsilanes: Stereoconvergent Transmetallation and Diastereoselective Aldol Reactions
Duffy, Joseph L.,Yoon, Tehshik P.,Evans, David A.
, p. 9245 - 9248 (2007/10/02)
Transmetallation of (E) and (Z) enolsilanes using halodialkylborane (R2BX) reagents provides predominantly the (Z) dialkylboron enolate under mild conditions.These enolates afford high levels of syn selectivity in subsequent aldol reactions.
Catalytic, Diastereoselective Aldol Reactions Using Titanium(IV) Halides
Mahrwald, Rainer
, p. 919 - 922 (2007/10/02)
The aldol reaction in the presence of titanium halides is described.Good yields of aldols 10-17 were obtained even with only catalytic amounts of titanium tetrafluoride.The reactions were carried out in the absence of a base. - Keywords: Aldol reaction /
Stereoselective Aldol Reaction Using Titanium Ate Complexes - An Efficient Method For Achieving Anti Aldol Selectivity
Mahrwald, Rainer
, p. 9015 - 9022 (2007/10/02)
Carbonyl compounds react in the presence of titanium ate complexes in the sense of an aldol reaction.The influence of ligands on controlling stereoselection of syn and anti aldol products of the titanium ate complexes used are described.High yield of anti
