L-proline-catalyzed three-component domino [3+2+1] annulation for the regio- and diastereoselective synthesis of highly substituted thienothiopyrans containing three or four stereocenters.
L-proline-catalyzed three-component reactions of ethyl 2-[(2-oxo-2-arylethyl)sulfonyl]acetate or ethyl 2-[(2-ethoxy-2-oxoethyl)sulfonyl]acetate, aromatic aldehydes, and 5-aryltetrahydro-3-thiophenone furnished a variety of highly substituted thieno[3,2-c]thiopyran derivatives. This facile transformation presumably occurs via a one-pot domino sequence of enamine formation/aldol condensation/Michael addition/6-exo-trig cyclization/elimination and involves the creation in a single operation of three C-C bonds and the generation of three new stereocenters with complete diastereoselectivity in all cases and a fourth one in ca. 7:3 diastereomeric ratio when starting from a 5-substituted tetrahydro-3-thiophenone derivative.
Indumathi
Sethuraman
S
Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021, India.
Perumal
Subbu
S
Menéndez
J Carlos
JC
D002384:Catalysis; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011392:Proline / Q000737:chemistry*; D011714:Pyrans / Q000737:chemistry*; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D011714:Pyrans; D013438:Sulfhydryl Compounds; C522033:thiopyran; D011392:Proline