821785-10-8Relevant academic research and scientific papers
Stereospecific reaction of α-carbamoyloxy-2-alkenylboronates and α-carbamoyloxy-alkylboronates with grignard reagents - Synthesis of highly enantioenriched secondary alcohols
Beckmann, Edith,Desai, Vidya,Hoppe, Dieter
, p. 2275 - 2280 (2004)
Highly enantioenriched secondary alcohols were synthesized by treatment of α-carbamoyloxy-2-alkenylboronates and α-carbamoyloxy-alkylboronates with Grignard reagents. An intermediary boronate complex was transformed stereospecifically to the corresponding secondary 2-alkenyl- and alkylboronates by migration of an introduced residue. Oxidative workup furnished the enantioenriched secondary alcohols.
Investigation of the Deprotonative Generation and Borylation of Diamine-Ligated α-Lithiated Carbamates and Benzoates by in Situ IR spectroscopy
Mykura, Rory C.,Veth, Simon,Varela, Ana,Dewis, Lydia,Farndon, Joshua J.,Myers, Eddie L.,Aggarwal, Varinder K.
supporting information, p. 14677 - 14686 (2018/11/20)
Diamine-mediated α-deprotonation of O-alkyl carbamates or benzoates with alkyllithium reagents, trapping of the carbanion with organoboron compounds, and 1,2-metalate rearrangement of the resulting boronate complex are the primary steps by which organoboron compounds can be stereoselectively homologated. Although the final step can be easily monitored by 11B NMR spectroscopy, the first two steps, which are typically carried out at cryogenic temperatures, are less well understood owing to the requirement for specialized analytical techniques. Investigation of these steps by in situ IR spectroscopy has provided invaluable data for optimizing the homologation reactions of organoboron compounds. Although the deprotonation of benzoates in noncoordinating solvents is faster than that in ethereal solvents, the deprotonation of carbamates shows the opposite trend, a difference that has its origin in the propensity of carbamates to form inactive parasitic complexes with the diamine-ligated alkyllithium reagent. Borylation of bulky diamine-ligated lithiated species in toluene is extremely slow, owing to the requirement for initial complexation of the oxygen atoms of the diol ligand on boron with the lithium ion prior to boron-lithium exchange. However, ethereal solvent, or very small amounts of THF, facilitate precomplexation through initial displacement of the bulky diamines coordinated to the lithium ion. Comparison of the carbonyl stretching frequencies of boronates derived from pinacol boronic esters with those derived from trialkylboranes suggests that the displaced lithium ion is residing on the pinacol oxygen atoms and the benzoate/carbamate carbonyl group, respectively, explaining, at least in part, the faster 1,2-metalate rearrangements of boronates derived from the trialkylboranes.
Bronsted acid catalyzed asymmetric reduction of ketones and acyl silanes using chiral anti -pentane-2,4-diol
Matsuo, Jun-Ichi,Hattori, Yu,Ishibashi, Hiroyuki
supporting information; experimental part, p. 2294 - 2297 (2010/08/05)
Ketones and acyl silanes were reduced to the corresponding alcohols by a simple procedure employing anti-1,3-diol and a catalytic amount (5 mol %) of 2,4-dinitrobenzenesulfonic acid in benzene at reflux. Asymmetric induction reached up to >99% ee when a chiral pentane-2,4-diol of 97% ee was used.
Asymmetric reduction of aliphatic ketones and acyl silanes using chiral anti-pentane-2,4-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid
Matsuo, Jun-Ichi,Hattori, Yu,Hashizume, Mio,Ishibashi, Hiroyuki
experimental part, p. 6062 - 6069 (2010/10/02)
Aliphatic ketones were reduced to the corresponding secondary alcohols by using anti-1,3-diol and a catalytic amount of 2,4-dinitrobenzenesulfonic acid (DNBSA) in benzene at reflux. Addition of 1-octanethiol in that media improved the efficiency of the reduction. Asymmetric reduction of aliphatic ketones was performed by using chiral anti-pentane-2,4-diol, and highly asymmetric induction (up to >99% ee) was observed in the reduction of tert-alkyl ketones. Asymmetric reduction of acyl silanes using chiral anti-pentane-2,4-diol and DNBSA proceeded efficiently in the absence of octanethiol and the corresponding α-silyl alcohols were obtained in high yields with high ees.
Design of small molecule ketoamide-based inhibitors of cathepsin K
Catalano, John G.,Deaton, David N.,Long, Stacey T.,McFadyen, Robert B.,Miller, Larry R.,Payne, J. Alan,Wells-Knecht, Kevin J.,Wright, Lois L.
, p. 719 - 722 (2007/10/03)
A novel series of ketoamide-based inhibitors of cathepsin K has been identified. Modifications to P2 and P3 elements were crucial to enhancing inhibitory activity. Although not optimized, a selected inhibitor was effective in attenua
