APPLICATION OF THE REICH IODOSO SYN-ELIMINATION FOR THE PREPARATION OF AN INTERMEDIATE APPROPRIATE FOR THE SYNTHESIS OF BOTH HEXACYCLIC STEROIDAL UNITS OF CEPHALOSTATIN-7
Sk. Kim et Pl. Fuchs, APPLICATION OF THE REICH IODOSO SYN-ELIMINATION FOR THE PREPARATION OF AN INTERMEDIATE APPROPRIATE FOR THE SYNTHESIS OF BOTH HEXACYCLIC STEROIDAL UNITS OF CEPHALOSTATIN-7, Tetrahedron letters, 35(39), 1994, pp. 7163-7166
Hecogenin acetate 5 was converted to an intermediate suitable for cons
truction of both ''North'' and ''South'' hexacyclic spiroketals presen
t in cephalostatin 7. The key chemical transformations involved are: (
I)the Reich iodoso syn-elimination of iodide 18; (2) Rhodium [II] cata
lyzed intermolecular oxygen alkylation of secondary neopentyl alcohol
21; and (3) Intramolecular Wadsworth-Emmons reaction to provide the es
ter precursor of aldehyde 4.