1,721,027 research outputs found
Highly enantioselective organocatalytic addition of unmodified aldehydes to N-Boc protected imines: one-pot asymmetric synthesis of ?-amino acids
No full textHighly enantioselective catalytic routes to Boc protected ?-amino aldehydes, ?-amino acids and ?-amino alcohols are presented. The organocatalytic asymmetric reactions between unmodified aldehydes and N-Boc protected aryl imines proceed with excellent chemo- and enantioselectivities to give the corresponding compounds in high yields with up to >19:1 dr and 93% to >99% ee
Organocatalytic asymmetric 5-hydroxypyrrolidine synthesis: a highly enantioselective route to 3-substituted proline derivatives
No full textA simple and concise catalytic asymmetric entry to tetrahydroxanthenones
No full textThe first catalytic asymmetric synthesis of tetrahydroxanthenones is presented. The simple organocatalytic enantioselective domino reactions between salicylic aldehyde derivatives and ?,?-unsaturated cyclic ketones proceed with excellent chemoselectivity to give the corresponding tetrahydroxanthenones in moderate to good yields and high enantioselectivities
Organocatalytic asymmetric multi-component [C+NC+CC] synthesis of highly functionalized pyrrolidine derivatives
No full textThe highly chemo- and enantioselective organocatalytic [C+NC+CC] coupling process between aldehydes, dialkyl 2-aminomalonates and ?,?-unsaturated aldehydes is presented. The reaction gives access to highly functionalized pyrrolidine derivatives in good yields with >10:1 dr and 90–98% ee
One-pot catalytic asymmetric cascade synthesis of cycloheptane derivatives
No full textA regiospecific, highly chemo-, diastereo-, and enantioselective one-pot catalytic cascade synthesis of cycloheptane derivatives is presented. In this chiral-amine-catalyzed asymmetric process, six new bonds and five new stereocenters were formed with excellent stereocontrol (>25:1 d.r. and 98- >99 ee)
Asymmetric amplification in the amino acid-catalyzed synthesis of amino acid derivatives
No full textThe origins of biological homochirality have intrigued researchers since Pasteur’s discovery of the optical activity of biomolecules. Herein, we present the first example of asymmetric amplification in the amino acid-catalyzed enantioselective synthesis of amino acid derivatives that provides support for a synergistic model for the evolution of homochirality by amino acid catalysis
Highly diastereo- and enantioselective catalytic domino thia-Michael/aldol reactions: synthesis of benzothiopyrans with three contiguous stereocenters
No full textHighly enantioselective organocatalytic domino thia-Michael/aldol reactions between 2-mercaptoacetophenone and ?,?-unsaturated aldehydes are presented. The reactions proceed with excellent chemo-, diastereo- and enantioselectivity to give the corresponding benzothiopyran derivatives in high yields with up to >15:1 dr and 96 to >99?% ee
One-pot pyrrolidine-catalyzed synthesis of benzopyrans, benzothiopyranes, and dihydroquinolidines
Full text linkA simple catalytic racemic synthesis of benzopyranes, benzothiopyranes and 1,2-dihydroquinolines is presented. The organocatalytic domino reactions between 2-heteroatom substituted aldehyde derivatives and ?,?-unsaturated aldehydes or ?,?-unsaturated cyclic ketones proceed with excellent chemoselectivity to give the corresponding products in good to high yields
Enantioselective organocatalytic conjugate addition of amines to ?,?-unsaturated aldehydes: one-pot asymmetric synthesis of ?-amino acids and 1,3-diamines
No full textOrganocatalytic asymmetric amine conjugate additions to ?,?-unsaturated aldehydes catalyzed by protected diarylprolinols are presented. The reactions proceed with high enantioselectivity and result in Cbz or Boc protected ?-amino aldehydes, ?-amino alcohols, ?-amino acids and 1,3-diamines with typically 82–99% ee
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