99773-69-0Relevant academic research and scientific papers
Enantioselective construction of tetrasubstituted stereogenic carbons through bronsted base catalyzed michael reactions: α′-hydroxy enones as key enoate equivalent
Badiola, Eider,Fiser, Bla,Gmez-Bengoa, Enrique,Mielgo, Antonia,Olaizola, Iurre,Urruzuno, Iaki,Garca, Jess M.,Odriozola, Jos M.,Razkin, Jess,Oiarbide, Mikel,Palomo, Claudio
, p. 17869 - 17881 (2015/02/19)
Catalytic and asymmetric 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 equivalents. It is found that the Michael addition of a range of enolizable carbonyl compounds that have previously demonstrated 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. 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 chemical 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 stereochemistry is also provided, and the proposed models are compared with related systems in the literature.
Palladium-catalyzed oxidative cyclizations: Synthesis of dihydropyranones and furanones
Reiter, Maud,Turner, Hazel,Mills-Webb, Rebecca,Gouverneur, Veronique
, p. 8478 - 8485 (2007/10/03)
A boron-mediated syn- and anti-stereoselective aldol reaction giving rise to various β-hydroxyenones was coupled to a Pd(II)-mediated oxidative cyclization to give 2,3,6-trisubstituted syn- and antidihydropyranones in good yields. The Pd(I
Catalytic enantioselective conjugate addition of carbamates
Palomo, Claudio,Oiarbide, Mikel,Halder, Rajkumar,Kelso, Michael,Gomez-Bengoa, Enrique,Garcia, Jesus M.
, p. 9188 - 9189 (2007/10/03)
Catalytic, asymmetric conjugate addition of carbamates to enoyl systems has been realized for the first time, providing a two-step access to virtually enantiopure N-protected β-amino acids. Copyright
STEREOSELECTIVE SYNTHESIS OF CIS-α,β-EPOXYESTERS AND ALDEHYDES VIA DIVALENT TIN ENOLATE. A SYNTHESIS OF 2-AMINO-2-DEOXY-D-ARABINITOL
Mukaiyama, Teruaki,Yura, Takeshi,Iwasawa, Nobuharu
, p. 809 - 812 (2007/10/02)
A convenient method for the stereoselective synthesis of cis-α,β-epoxyesters and aldehydes is established according to the Sn(OTf)2 mediated cross aldol reaction between α-bromo-α'-silyloxyketone and aldehyde.The reaction is applied to the stereoselective synthesis of 2-amino-2-deoxy-D-arabinitol.
