118356-98-2Relevant academic research and scientific papers
Zirconium-Catalyzed Hydroalumination of C=O Bonds: Site-Selective De- O-acetylation of Peracetylated Compounds and Mechanistic Insights
Courant, Thibaut,Gavel, Marine,Renard, Romain M. Q.,Gandon, Vincent,Joosten, Antoine Y. P.,Lecourt, Thomas
, p. 9280 - 9288 (2021/06/30)
An unprecedented hydroalumination of C = O bonds catalyzed by zirconocene dichloride is reported herein and applied to the site-selective deprotection of peracetylated functional substrates. A mixed metal hydride, with 1:1 zirconium/aluminum stoichiometry
Regio- A nd chemoselective deprotection of primary acetates by zirconium hydrides
Gavel, Marine,Courant, Thibaut,Joosten, Antoine Yvan Philippe,Lecourt, Thomas
supporting information, p. 1948 - 1952 (2019/04/10)
A combination of DIBAL-H and Cp2ZrCl2 is shown to promote the regioselective cleavage of primary acetates on a broad scope of substrates, ranging from carbohydrates to terpene derivatives, with a high tolerance toward protecting groups and numerous functionalities found in natural products and bioactive compounds. Apart from providing highly valuable building blocks in only two steps from biosourced raw materials, this selective de-O-acetylation should also be strongly helpful to solve selectivity issues in organic synthesis.
Solid-surface activated recombinant: Rhizopous oryzae lipase expressed in Pichia pastoris and chemically modified variants as efficient catalysts in the synthesis of hydroxy monodeprotected glycals
Filice, Marco,Molina, Marta,Benaiges, M. Dolors,Abian, Olga,Valero, Francisco,Palomo, Jose M.
, p. 1766 - 1775 (2017/07/22)
Lipase of Rhizopus oryze expressed in Pichia pastoris (ROLpp) was selectively immobilized on octyl-Sepharose, fixing the open and active conformations. This enzyme was compared to the commercial one (ROLsigma) and a unique enzyme of 32 kDa was selectively adsorbed in both cases. Small differences in the N-terminal peptide sequence of both lipases seem to be involved in the enzyme fixing on the solid support, affecting the active site structure. This phenomenon resulted in a strong difference in catalytic properties between immobilized enzymes, with ROLpp being the most active, specific and regioselective heterogeneous biocatalyst in the hydrolysis of lactal hexaacetate. Immobilized ROLpp was 8 times more active, and more specific than immobilized ROLsigma, with excellent regioselectivity (monodeprotection in 3-OH, >99% yield). Solid-phase chemical modification of the N-terminus of immobilized ROLpp was attempted because of the moderate results obtained in the hydrolysis of glucal triacetate. Different biomolecules were introduced and the enzyme catalytic properties in this reaction were assessed. The modification of ROLpp with a polycarboxylated peptide (pA) improved the activity, specificity and regioselectivity of the enzyme, producing mainly the 3-OH monodeprotected glucal. The presence of acetonitrile 3% (v/v) in the reaction medium negatively affected ROLpp, being completely unspecific, whereas ROLpp modified with p1 conserved the specificity and regioselectivity shown in fully aqueous medium. The presence of dioxane improved the specificity and varied the regiopreference of the immobilized lipase (from C-3 to C-6 and C-4 monohydrolyzed products). The posterior modification with pA improved the specificity and the regio-preference of ROLpp towards C-6 monohydrolyzed product.
THE ALKYLATION AND ACYLATION OF GLYCALS VIA AN INITIALIZING ELECTROCHEMICAL STEP
Fischer, Susanne,Hamann, Carl Heinz
, p. 327 - 340 (2007/10/02)
The method of electrochemically induced formation of ether and ester derivatives of saturated mono- and disaccharides was applied to 1,2-unsaturated monosaccharides (D-glycals).The influence of the supporting electrolyte on the product distribution was investigated by variation of the cation.To provide data for comparison, alkylation was also carried out chemically in the presence of different bases, e.g.LiH and NaH.
