Highly stereoselective hetero Diels-Alder reactions of chiral 3-(p-tolylsulfinyl)-2-furaldehyde with Danishefsky's diene promoted by a lanthanoid Lewis acid

✍ Scribed by Yoshitsugu Arai; Tsutomu Masuda; Yukio Masaki; Motoo Shiro

• Book ID: 103977475
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 359 KB
• Volume: 7
• Category: Article
• ISSN: 0957-4166
• DOI: 10.1016/0957-4166(96)00126-7

✦ Synopsis

Hetero Diels-Alder reactions of optically active 3-(p-tolylsulfinyl)-2furaldehyde with 1-methoxy-3-(trimethylsilyloxy)-buta-l,3-diene (Danishefsky's diene) in the presence of a Lewis acid has been examined. The reaction in the presence of 1.0 equiv, of Ln(OTf)3 (Ln = Yb, Nd and Sin) followed by acidic workup produced in good yields (68-88%) the hetero Dieis-Alder adduct with high diastereoisomedc excesses (93-98% d.e.'s), whereas in the presence of an NMR shift reagent, tris(2,2,6,6-tetramethyl-3,5-heptanedionate)europium [Eu(thd)3] the corresponding diastereoisomer was obtained as the major adduct in excellent yield with 77% d.e.