title: Organocatalytic enantioselective hydroxymethylation of oxindoles with paraformaldehyde as C1 unit.
abstract: A bifunctional thiourea-tertiary amine-catalyzed asymmetric hydroxymethylation of 3-substituted oxindoles using paraformaldehyde as the C1 unit was developed. A wide scope of oxindoles, bearing C3 sterically congested quaternary carbon centers, were smoothly obtained in good to excellent yields (up to 99%) and high enantioselectivities (up to 91% ee) under mild reaction conditions. A more significant feature of this approach employs cheap and readily available paraformaldehyde as a hydroxymethylation C1 unit, which is activated by chiral bifunctional thiourea organocatalysts.
authors.affiliation: Key Laboratory for Asymmetric Synthesis & Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Beijing 100049, China.
authors.forename: Xiong-Li
authors.initials: XL
authors.lastname: Liu
authors.forename: Yu-Hua
authors.initials: YH
authors.lastname: Liao
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Wu
authors.forename: Lin-Feng
authors.initials: LF
authors.lastname: Cun
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Wei-Cheng
authors.initials: WC
authors.lastname: Yuan
mesh_terms: D002384:Catalysis; D005557:Formaldehyde / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D008745:Methylation; D015394:Molecular Structure; D000078183:Oxindoles; D011108:Polymers / Q000737:chemistry*; D013237:Stereoisomerism; D013890:Thiourea / Q000737:chemistry
chemical_list: D007211:Indoles; D000078183:Oxindoles; D011108:Polymers; C022960:2-oxindole; D005557:Formaldehyde; D013890:Thiourea; C003043:paraform