High-Yield Synthesis of 20-, 24-, and 28-Membered Macropentolide, -hexolide, and -heptolide, Respectively, from (R)- or (S)-3-hydroxybutanoic acid under Yamaguchi's macrolactonization conditions
✍ Scribed by Dieter Seebach; Urs Brändli; Peter Schnurrenberger; Michael Przybylski
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- German
- Weight
- 728 KB
- Volume
- 71
- Category
- Article
- ISSN
- 0018-019X
No coin nor oath required. For personal study only.
✦ Synopsis
The macrocyclic pentolide 1, hexolide 2, and heptolide 3 constitute ca. 80% of the oligomers formed in ca. 50% yield from enantiomerically pure 3-hydroxybutanoic acid under Yamaguchi's macrolactonization conditions. The FAB mass spectra of the MH', MNaf, and MCsf are reported (Figs. 2, 3, 5, and 6 ) . No cyclic tetramer is detected. The 'H-NMR spectra of the cyclic oligomers, of the monomer, and of the polymer (PHB) are very similar (Fig. ) . Directed synthesis of the open-chain dimer and tetramer of 3-hydroxybutanoic acid and attempted cyclization do not lead to the isolation of the cyclic tetramer.
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For a partial preliminary communication, see our recent review on the use of the biopolymer PHBjPHV for EPC syntheses [l]. Most results reported in this paper are part of the planned Ph. D. thesis of (i. B., ETH Zurich. First observation of the selective macrocyclization described here (Zurich, 1984); present address of P. Sch.: F. Hoffmann-La Roche & Co. AG, Bau 29/205, VPIBS, Grenzacherstrasse 124, CH4002