The absolute configurations of laureatin and isolaureatin

✍ Scribed by E. Kurosawa; A. Furusaki; M. Izawa; A. Fukuzawa; T. Irie

• Publisher: Elsevier Science
• Year: 1973
• Tongue: French
• Weight: 191 KB
• Volume: 14
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)87057-x

✦ Synopsis

In previous papers (1,2,3), the structures and stereochemistry of laureatin (I) and lsolaureatln (II), C15H2C02Br2, isolated from Laurenci_a_ nipponLca Yainada, have been proposed by the views of thler physical and chemical propertles and biogenetical point of view. CH3-(CH2),-;H-;H-(CH2)q-CH3 The conflguratlons at C-6 and C-7 (S and S) have been determlned by means of optlcal rotation of glycol dlacet?te (III), derived from I (zinc-acetlc acid, H2/Pt02 and acetylation), *c# which was antipode of diacetate (IV) from laurencin (V) (4.5,6). The stereochemical relatlonshlp between ether oxygen at C-9 and bromine at C-1C In I was proposed as trans by the observation of zinc-acetic acid degradation of hexahydromonodebromolaureatl? (VI) (1,3), yleldlng smoothly unsaturated cyclic ether (VII) and coupling constant (2.5 Hz) between protons at C-9 and C-lG, arlslng from dihedral angle of 60'. Consequently, each center at C-9 and C-10 would be reasonably assigned as R-configuration.