Ring contraction of hydroporphinoid to corrinoid complexes

V Rasetti; A Pfaltz; C Kratky; A Eschenmoser

doi:10.1073/pnas.78.1.16

Ring contraction of hydroporphinoid to corrinoid complexes

Proc Natl Acad Sci U S A. 1981 Jan;78(1):16-9. doi: 10.1073/pnas.78.1.16.

Authors

V Rasetti¹, A Pfaltz, C Kratky, A Eschenmoser

Affiliation

¹ Laboratory of Organic Chemistry, Eidgenössische Technische Hochschule Zürich, Universitätstrasse 16, CH-8092 Zürich, Switzerland.

Abstract

Crystalline nickel(II) and dicyanocobalt(III) complexes of a racemic 1,2,2,7,7,12,12,17,17,20-decamethyl-20-hydroxy-1,2,3,7,8,12,13,20-octahydro- 17H-porphyrin rearrange to the corresponding complexes of racemic 19-acetyl-1,2,2,7,7,12,12,17,17-nonamethyl-trans-corrin on melting (approximately 290 degrees C and 260 degrees C, respectively). The nickel(II) 19-acetylcorrinate formed in this way is shown to deacetylate to racemic nickel(II) 1,2,2,7,7,12,12,17,17-nonamethyl-trans-corrinate on treatment with 2 M KOH. These reactions are being studied as potentially biomimetic chemical models for the elusive ring contraction step in vitamin B(12) biosynthesis.