Short and Efficient Synthesis of Chiral Furyl Carbinols from Carbohydrates

Abstract

Common sugar derivatives can be transformed in a few steps into chiral-substituted furyl carbinols. The mildness of the reaction conditions and the good yields obtained make this procedure an interesting alternative to the conventional processes.

Chemistry of Polyvalent Iodine

“…498 The same authors have developed an efficient procedure for the selective removal from carbohydrate substrates of methoxy protecting groups next to hydroxy groups by treatment with the DIB-I 2 system 499…”

An Alkyne Hydroacylation Route to Highly Substituted Furans

“…[3][4][5] In addition, a broad range of aldehydes can now be employed, and particularly in the case of alkyne hydroacylation, significant substitution of the unsaturated component can be tolerated, thus allowing for the regioselective production of highly substituted complex molecules in one catalytic intermolecular carbon-carbon bond forming step. Herein, we demonstrate the utility of intermolecular alkyne hydroacylation in the efficient synthesis of di-and trisubstituted furans and related heterocycles.g-Hydroxy-a,b-enones are known to undergo acid-catalyzed dehydrative cyclization to form furans, and this transformation has been exploited by several research groups, [6] most notably in the recent work from Donohoe et al [7] The intermolecular hydroacylation of an aldehyde with readily available propargylic alcohols would permit the synthesis of g-hydroxy-a,b-enones with 100 % atom efficiency; coupling this carbon-carbon bond formation with an acid-catalyzed dehydrative cyclization would allow for the regioselective synthesis of di-or trisubstituted furans. The associated disconnection is novel for this type of heterocycle (Scheme 2).…”

“Cut and Paste” Processes in the Search of Bioactive Products: One-Pot, Metal-free O-Radical Scission-Oxidation-Addition of C, N or P-Nucleophiles

“…The addition of C -nucleophiles to oxycarbenium ions derived from the scission of carbohydrates has also been studied, as shown by the conversion 37→ 39 ( Boto, Hernández et al, 2007c ). In this case, however, the one-pot procedure was less efficient than the two-step process, where the intermediate acetate 38 was isolated and then treated with a Lewis acid and the C -nucleophile.…”

“…In effect, the scission generates a C -radical that can be readily oxidized to a cationic intermediate when the latter is stabilized by adjacent groups. This is the case for tertiary C -radicals, or those adjacent to nitrogen or electron-rich oxygen functionalities ( Boto et al, 1999 – 2004 ; 2005a ; 2007a ; 2007b ; 2007c ; 2007d ; Francisco et al, 2001 ; Romero-Estudillo, 2013 , 2015a , 2015b ; Kiyokawa et al, 2017 ; André-Joyaux et al, 2019 ). When the substrates are aminoacids or β-hydroxyamines, an intermediate iminium ion is formed, while carbohydrate substrates afford oxycarbenium ion intermediates.…”