51615-31-7Relevant academic research and scientific papers
Active Base Hybrid Organosilica Materials based on Pyrrolidine Builder Units for Fine Chemicals Production
Llopis, Sebastián,Velty, Alexandra,Díaz, Urbano
, p. 5012 - 5024 (2021/10/19)
The catalytic activity of “pyrrolidine type” fragments included or anchored in the mesoporous silica supports or polymeric frameworks have been fully reported for enantioselective transformation. Nevertheless, low attention was focused on their catalytic abilities to perform base-catalyzed reaction. Accordingly, hybrid materials including pyrrolidine fragments in the mesoporous silica supports were prepared following different synthesis methods, such as micellar and fluoride sol-gel routes in absence of structural directing agents. Their great catalytic performance was explored for various base-catalyzed reactions to the formation of C?C bond through Knoevenagel, Claisen-Schmidt and Henry condensations under microwave irradiation. The benefits of microwave irradiation combined with suitable catalytic properties of pyrrolidine hybrid materials with strong base sites and high accessibility to active centers, allowed carrying out successfully base-catalyzed condensation reactions for the production of fine chemicals. Moreover, the hybrid catalyst exhibited high selectivity and good stability over different catalytic cycles contributing to environmental sustainability.
Mechanism for photodecomposition of naphtho[1,8-de][1,3] dithiin-1-bis(ethoxycarbonyl)methylides
Fujii, Takayoshi,Sakuragi, Hirochika,Furukawa, Naomichi
, p. 8039 - 8042 (2007/10/02)
Naphtho[1,8-de][1,3]dithiin-1-bis(ethoxycarbonyl)methylides (3) were prepared by the reaction of naphtho[1,8-de]dithiins with diethyl diazomalonate in the presence of copper acetylacetonate. The sulfonium ylides 3 underwent photo-rearrangement giving olefin 5 quantitatively together with naphthalene-1,8-dithiole.
Chemoenzymatic Preparation of Asymmetrized Tris(hydroxymethyl)methane (THYM*) and of Asymmetrized Bis(hydroxymethyl)acetaldehyde (BHYMA*) as New Highly Versatile Chiral Building Blocks
Guanti, Giuseppe,Banfi, Luca,Narisano, Enrica
, p. 1540 - 1554 (2007/10/02)
A series of asymmetrized tris(hydroxymethyl)methanes 2 and bis(hydroxymethyl)acetaldehydes 3 have been prepared in both enantiomeric forms through a chemoenzymatic methodology.The key step is the highly enantioselective PPL-catalyzed monohydrolysis of 2(E)-alkenyl-1,3-diacetoxypropanes 25-27.A careful study on the effect of unsaturations adjacent to the prochiral center in a series of 2-substituted 1,3-diacetoxypropanes has confirmed the suggested beneficial effect of a ? system in that position but has also unveiled an unprecedented dramatic effect of double-bond configuration on enantioselectivity.A new empirical model for the interpretation of these and other results, based both on polarity and steric arguments, is proposed.This study provides a general protocol for the efficient synthesis of asymmetrized 1,3-propanediols bearing in position 2 saturated or unsaturated carbon chains.
REACTIONS OF TITANIUM DERIVATIVES OF CERTAIN CH ACIDS WITH CARBONYL COMPOUNDS. I. CROTONIC CONDENSATIONS WITH THE TITANIUM DERIVATIVES OF MALONIC ESTER, CYANOACETIC ESTER, AND MALONONITRILE
Kasatkin, A. N.,Biktimirov, R. Kh.,Tolstikov, G. A.,Khalilov, L. M.
, p. 1029 - 1037 (2007/10/02)
The titanium derivatives of malonic ester, cyanoacetic ester, and malononitrile obtained by the reaction of the corresponding sodium salts with (i-PrO)3TiCl, react with aldehydes in THF at -78 to 20 deg C, forming the products from crotonic condensation.If α,β-unsaturated aliphatic α-bromo and keto aldehydes are used, the yields of the corresponding alkylidenemalonic and alkylidenecyanoacetic esters are substantially higher than under the conditions of the Knoevenagel reaction.
Tellurium-Assisted Cycloprpanation and Alkylidenation of α,β-Unsaturated Carbonyl Compounds with Dibromomalonic Esters
Matsuki, Toshiaki,Hu, Nan Xing,Otsubo, Tetsuo,Ogura, Fumio
, p. 2105 - 2107 (2007/10/02)
Dibutyl telluride assists cyclopropanation of α,β-unsaturated ketone, ester, and nitrile with dibromomalonic esters without solvent at room temperature.In addition, it effects alkylidenation of aldehydes including α,β-unsaturated aldehyde with the same reagent.
