Enantioselective Catalysis on the Solid Phase: Synthesis of Natural Product-Derived Tetrahydropyrans Employing the Enantioselective Oxa-Diels–Alder Reaction

✍ Scribed by Miguel A. Sanz; Tobias Voigt; Herbert Waldmann

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 208 KB
• Volume: 348
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/adsc.200606026

✦ Synopsis

Abstract

Aliphatic aldehydes were synthesized on a solid support and subjected to an enantioselectively catalyzed oxa‐Diels–Alder reaction with Danishefsky’s diene. Employing 5 mol % of a Cr(III)‐salen catalyst enantiomeric ratios up to>99 % and yields up to 40 % over five steps were achieved. Further elaboration of the polymer‐bound dihydropyrones was performed by subsequent conjugate cuprate addition, reduction of the ketone and transformation of the resulting alcohol to a carbamate yielding 2,4,6‐trisubstituted tetrahydropyrans after cleavage from the solid support.