Organoiron complexes in organic synthesis. Part 7. Regio- and stereo-chemistry of ring connection reactions relevant to steroid and terpene synthesis. X-Ray crystal structure determination of tricarbonyl(methyl 1-[2–5-η-4-methoxy-1-methylcyclohexa-2,4-dienyl]-3-hydroxymethyl-3-methyl-2-oxocyclohexanecarboxylate)iron

Abstract

Reaction of tricarbonyl(1–5-η-4-methoxy-1-methylcyclohexadienylium)iron hexafluorophosphate (1) with enolate anions of derivatives of methyl 2-oxocyclohexanecarboxylate and methyl 1-oxotetralin-2-carboxylate occurs with very high regioselectivity for the methylated dienylium terminus. The structure and stereochemistry of one of the products (18) was determined by X-ray crystallography and found to be in agreement with that derived from spectroscopic data.