Stereoselective Synthesis of Alcohols, XXXII. Synthesis of the Prelog-Djerassi Aldehyde and of a C-1/C-9 Segment of 6-Deoxyerythronolide

✍ Scribed by Hoffmann, Reinhard W. ;Ladner, Wolfgang ;Ditrich, Klaus

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 665 KB
• Volume: 1989
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.198919890239

✦ Synopsis

Pentenylboronates / Asymmetric induction / Stereoselectivity / Prelog-Djerassi aldehyde Because of the large number of contiguous stereogenic centers, the synthesis of polyketide-derived natural products has to meet the criteria of both efficiency and stereoselectivity. A milestone in this respect is the synthesis of 6-deoxyerythronolide €3 by the Masamune group2). The key sequence involves the conversion of the "Masamune aldehyde" 1 into the "Prelog-Djerassi aldehyde" 2 and that of the latter into the C-l/C-9 building block 3 of 6-deoxyerythronolide. This synthesis set a standard against which new reagents and new developments in stereoselective synthesis are to be measured. Following Masamune's earlier studies 3), cf. also reE4', a number of groups investigated the chain extension of the Scheme I 0 0 4 steps using chiral 1 enolates 0 n 3 steps using c chiral 80 Yo As the minor isomer 15 found by Santelli-Rouvier is not identical to 13, it signals that it stems from the reaction of the same enantiomeric pair [(2S*)-1 + (S*)-12] that leads