Intramolecular condensation of steroidal 17α-formyl-17β-acetates: Synthesis of 14-hydroxymethyl-3-oxo-19-nor-17α-pregn-4-ene-21,17-carbolactone

✍ Scribed by James R Bull; Lynne M Steer

• Publisher: Elsevier Science
• Year: 1989
• Tongue: French
• Weight: 193 KB
• Volume: 30
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)93385-4

✦ Synopsis

Intramolecular condensation of steroidal Ilfi-acetoxy-17a-carbaldehydes offers a synthetic route to 19-nor-17,17-spirofactones. A cycloaddition-mediated route to ring D modified 19-not-steroids has recently been described, 2 in which 17~-acetoxy-3-methoxyestra-1,3,5(10)-triene-14,l7a-dicarbaldehyde(1) is readily prepared by oxidative cleavage of a ring D bridged intermediate. The stereochemically defined array of 14,17-functionality in (1) invited exploration of a novel approach to the synthesis of 14-functionalised 19-nor analogues of spironolactone.3 It was reasoned that an enolate derived from the 17&acetoxy group should condense selectively with the proximate 17a-formyl group, and that the resultant 17,17spirolactone could readily be modified to the desired analogues (Scheme 1).