Bifunctional Squaramide Organocatalysts for the Asymmetric Addition of Formaldehyde tert‐Butylhydrazone to Simple Aldehydes. Issue 26 (26th April 2018)

• Record Type: Journal Article
• Authors: Matador, Esteban; de Gracia Retamosa, María; Monge, David; Iglesias‐Sigüenza, Javier; Fernández, Rosario; Lassaletta, José M.
• Is Part Of: Chemistry. Volume 24:Issue 26(2018)
• Page Start: 6854
• Page End: 6860
• Publication Date: 2018-04-26
• Subjects: hydrogen bonds -- hydrazones -- organocatalysis -- squaramides -- solvent effects; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201801052
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The nucleophilic addition of formaldehyde tert ‐butylhydrazone to simple aldehydes (a formal hetero‐carbonyl–ene reaction) can be performed with good reactivity and excellent enantioselectivity by virtue of the dual hydrogen‐bonding activation exerted by amide–squaramide organocatalysts. The resulting hydroxydiazenes (azo alcohols) were isolated in high yields as enantiomerically enriched azoxy compounds after a regioselective azo‐to‐azoxy transformation. Subsequent derivatization provides an entry to relevant amino alcohols, oxazolidinones, and derivatives thereof. Abstract : Two heads are better than one : Bifunctional amide–squaramide catalysts enabled the highly enantioselective addition of formaldehyde tert ‐butylhydrazone to simple aldehydes (see scheme; MMPP=magnesium monoperoxyphthalate). Subsequent derivatizations provide an entry to relevant amino alcohols, oxazolidinones, and derivatives thereof.