Badiola, Eider; Fiser, Bela; Gomez-Bengoa, Enrique; Mielgo, Antonia; Olaizola, Iurre; Urruzuno, Inaki; Garcia, Jesus M.; Odriozola, Jose M.; Razkin, Jesus; Oiarbide, Mikel; Palomo, Claudio published the artcile< Enantioselective Construction of Tetrasubstituted Stereogenic Carbons through Bronsted Base Catalyzed Michael Reactions: α'-Hydroxy Enones as Key Enoate Equivalent>, Reference of 112-63-0, the main research area is hydroxy enone enoate equivalent Michael acceptor hydrogen bond; chiral bifunctional Bronsted base catalysis diastereoselective enantioselective Michael; Michael addition oxy enone oxindole cyanoester oxazolone thiazolone azlactone.
Catalytic and asym. Michael reactions constitute very powerful tools for the construction of new C-C bonds in synthesis, but most of the reports claiming high selectivity are limited to some specific combinations of nucleophile/electrophile compound types, and only few successful methods deal with the generation of all-carbon quaternary stereocenters. A contribution to solve this gap is presented here based on chiral bifunctional Bronsted base (BB) catalysis and the use of α’-oxy enones as enabling Michael acceptors with ambivalent H-bond acceptor/donor character, a yet unreported design element for bidentate enoate equivalent It is found that the Michael addition of a range of enolizable carbonyl compounds that have been previously demonstrated as challenging (i.e., α-substituted 2-oxindoles, cyanoesters, oxazolones, thiazolones, and azlactones) to α’-oxy enones can afford the corresponding tetrasubstituted carbon stereocenters in high diastereo- and enantioselectivity in the presence of standard BB catalysts [e.g., I + II → III with R = CH2CH2Ph and R1 = Ph]. Experiments show that the α’-oxy ketone moiety plays a key role in the above realizations, as parallel reactions under identical conditions but using the parent α,β-unsaturated ketones or esters instead proceed sluggish and/or with poor stereoselectivity. A series of trivial chem. manipulations of the ketol moiety in adducts can produce the corresponding carboxy, aldehyde, and ketone compounds under very mild conditions, giving access to a variety of enantioenriched densely functionalized building blocks containing a fully substituted carbon stereocenter. A computational investigation to rationalize the mode of substrate activation and the reaction stereochem. is also provided, and the proposed models are compared with related systems in the literature.
Journal of the American Chemical Society published new progress about Aldehydes Role: SPN (Synthetic Preparation), PREP (Preparation). 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, Reference of 112-63-0.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics