14643-62-0Relevant academic research and scientific papers
Synthesis and antioxidant characteristics of borate esters used in lubricating oil
Shekarriz,Ghanbari,Taghipoor,Khalili,Hajialiakbari,Adibi,Soleymani
experimental part, p. 3646 - 3652 (2010/11/04)
In the present studies, the preparation of esters of boric acid with hindered phenols is reported, wherein the alkyl groups are branched on the α-carbon atoms. The products were evaluated in terms of their oxidative stability. In most cases, improvements in oxidative stability in ahydrocarbon media (cumene) were observed.
Catalytic asymmetric aziridination with borate catalysts derived from VANOL and VAPOL ligands: Scope and mechanistic studies
Zhang, Yu,Desai, Aman,Lu, Zhenjie,Hu, Gang,Ding, Zhensheng,Wulff, William D.
experimental part, p. 3785 - 3803 (2009/05/28)
An extended study of the scope and mechanism of the catalytic asymmetric aziridination of imines with ethyl diazoacetate mediated by catalysts prepared from the VANOL and VAPOL ligands and triphenylborate is described. Nonlinear studies with scalemic VANOL and VAPOL reveal an essentially linear relationship between the optical purity of the ligand and the product suggesting that the catalyst incorporates a single molecule of the ligand. Two species are present in the catalyst prepared from B(OPh)3 and either VANOL or VAPOL as revealed by 1H NMR studies. Mass spectral analysis of the catalyst mixture suggests that one of the species involves one ligand molecule and one boron atom (B1) and the other involves one ligand and two boron atoms (B2). The latter can be formulated as either a linear or cyclic pyroborate and the 11B NMR spectrum is most consistent with the linear pyroborate structure. Several new protocols for catalyst preparation are developed which allow for the generation of mixtures of the B1 and B2 catalysts in ratios that range from 10:1 to 1:20. Studies with catalysts enriched in the B1 and B2 species reveal that the B2 catalyst is the active catalyst in the VAPOL catalyzed asymmetric aziridination reaction giving significantly higher asymmetric inductions and rates than the B1 catalyst. The difference is not as pronounced in the VANOL series. A series of 12 different imines were surveyed with the optimal catalyst preparation procedure with the finding that the asymmetric inductions are in the low to mid 90s for aromatic imines and in the mid 80s to low 90s for aliphatic imines for both VANOL and VAPOL catalysts. Nonetheless, the crystallinity of the N-benzhydryl aziridines is such that nearly all of the 12 aziridine products screened can be brought to >99% ee with a single recrystallization.
A new regio- and stereoselective intermolecular Friedel-Crafts alkylation of phenolic substrates with aryl epoxides
Bertolini, Ferruccio,Crotti, Paolo,Macchia, Franco,Pineschi, Mauro
, p. 61 - 64 (2007/10/03)
A conceptually new regioselective and highly syn-stereoselective intermolecular Friedel-Crafts-type O-alkylation of phenols with aryl epoxides by the use of appropriately substituted aryl borates is reported. The carbon-carbon bond formation occurs in neutral and mild conditions without the need for external Lewis acids or transition metal catalysts.
Facile regio- and stereoselective carbon-carbon coupling of phenol derivatives with aryl aziridines
Pineschi, Mauro,Bertolini, Ferruccio,Crotti, Paolo,Macchia, Franco
, p. 2627 - 2630 (2007/10/03)
A chemo-, regio-, and stereoselective direct carbon-carbon coupling of readily available aryl borates with N-protected aryl aziridines provides a method for the synthesis of new 2-(o-hydroxyaryl)-2-aryl ethylamines which can be used, in a novel annulation
