title: Enantioselective Diels-Alder-lactamization organocascades employing a furan-based diene.
abstract: α,β-Unsaturated acylammonium salts are useful dienophiles enabling highly enantioselective and stereodivergent Diels-Alder-initiated organocascades with furan-based dienes. Complex polycyclic systems can thus be obtained from readily prepared dienes, commodity acid chlorides, and a chiral isothiourea organocatalyst under mild conditions. We describe the use of furan-based dienes bearing pendant sulfonamides leading to the generation of oxa-bridged, trans-fused tricyclic γ-lactams. This process constitutes the first highly enantio- and diastereoselective, organocatalytic Diels-Alder cycloadditions with these typically problematic dienes due to their reversibility. Computational studies suggest that the high diastereoselectivity with these furan dienes may be due to a reversible Diels-Alder cycloaddition for the endo adducts. In addition, the utility of this methodology is demonstrated through a concise approach to a core structure with similarity to the natural product isatisine A and a nonpeptidyl ghrelin-receptor inverse agonist.
authors.affiliation: Department of Chemistry and Biochemistry, Baylor University, One Bear Place 97348, Waco, Texas 76798, USA. Daniel_Romo@baylor.edu.
authors.forename: Mikail E
authors.initials: ME
authors.lastname: Abbasov
authors.forename: Brandi M
authors.initials: BM
authors.lastname: Hudson
authors.forename: Weixu
authors.initials: W
authors.lastname: Kong
authors.forename: Dean J
authors.initials: DJ
authors.lastname: Tantillo
authors.forename: Daniel
authors.initials: D
authors.lastname: Romo
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D005663:Furans / Q000737:chemistry*; D007769:Lactams / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D000475:Alkenes; D005663:Furans; D007769:Lactams; C039281:furan