Stereoselective Intramolecular Cyclization of Allyl and Homoallyl Benzamide via π-Allylpalladium Complex Catalyzed by Pd(0)

• Published in: Journal of organic chemistry Vol. 64; no. 26; pp. 9450 - 9458
• Main Authors: Lee, Kee-Young, Kim, Yong-Hyun, Park, Min-Sung, Oh, Chang-Young, Ham, Won-Hun
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 24.12.1999; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; STATINE ANALOGS; ASYMMETRIC-SYNTHESIS; FACILE SYNTHESIS; HYDROXY-BETA-AMINO; ENANTIOSELECTIVE SYNTHESIS; DIASTEREOSELECTIVE SYNTHESIS; BUILDING-BLOCKS; EFFICIENT SYNTHESIS; TAXOL SIDE-CHAIN; OXIDATIVE ADDITION
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo991065r

The transformation of acyclic allylic benzamides 4 and homoallylic benzamides 12 to vinyl oxazolines 3 is achieved in the presence of base by the catalysis of Pd(0) in high yield and with high diastereoselectivity. Especially, in the case of homoallylic benzamides 12, trans-oxazolines 3 are formed exclusively or predominantly over cis-oxazolines 8, irrespective of the composition of their stereoisomers. The reaction is believed to proceed via the same π-allylpalladium complex that arises from either primary or secondary allylic acetates. We applied this method to the syntheses of β-amino-α-hydroxy acids 1 and γ-amino-β-hydroxy acids 2, conveniently protected as oxazoline.