THE TOTAL SYNTHESIS OF A NON-BENZENOID STEROID¹

Abstract

Pure pentanol-3 was required in large quantity for work in progress in this Laboratory. Since the physical constants for the carbinol reported in the literature1 show wide disagreement, a study was made on the purity of material synthesized in the laboratory and that obtained from Sharpies Solvents Corporation.Propionaldehyde, b. p. 48.0°at 736 mm., re20D 1.3636, was prepared by dehydrogenation of re-propyl alcohol with a copper catalyst. It was treated in four 8-mole lots with ethylmagnesium chloride in anhydrous ethyl ether. The crude product obtained in 67% yield after distillation through a column of approximately 25 theoretical(1) Brunei,

A + D → Ad → Abcd

“…Also outlined in Scheme 8-6 is a synthetic sequence remarkable for its simplicity [54][55][56][57][58]. The starting dienynes 63 were readily obtained from dehydration of the corresponding acetylenic glycols which were in turn prepared from acetylene and the appropriate cycloalkanones [59].…”

Enyne [4 + 4] Photocycloaddition: Bridged 1,2,5-Cyclooctatrienes

“…One hundred and fifteen years ago, the thermal dimerization of phenylpropiolic acid was described, a “dehydro-Diels−Alder” reaction in which an enyne portion of the phenylacetylene combines in a [4 + 2] cycloaddition to another alkyne, followed by hydrogen migration to yield a new aromatic ring. − Forty years later, C. S. Marvel found that enynes would undergo a similar reaction with maleic anhydride at 130 °C. , In recent years new versions of this cycloaddition have been shown to be a powerful method for construction of substituted aromatics from enynes and alkynes. , …”