The Synthesis of Condensed Ring Compounds. Iii. A Hexahydronaphthalene Derivative From a Dieneyne

Abstract

In the preceding paper (1) it was shown that 1,3,5-hexatriene might serve as the basis of a general synthetic method for condensed ring compounds of angular construction, such as steroids, since it was possible to secure, as the principal product of its addition to a cyclohexene, a derivative of 1-vinyloctahydronaphthalene with the annular double bond probably in the 2,3-position. The utility of this intermediate in the synthesis of angular polycyclic compounds would depend on its ability to isomerize to a 1-vinyl-l-octalin which could then add a dienophile. Before the feasibility of this procedure could be tested, we had observed that a 1,5-diene-3-yne can add two molecules of dienophile to give a crystalline product and it has now been found that this addition proceeds in the manner required for the synthesis of compounds of the type sought. In 1933 Blomquist and Marvel (2) found that both 4,7-di-n-propyl-3,7-decadiene-5-yne and 6,9-dimethyl-5,9-tetradecadiene-7-yne added two moles of maleic anhydride in boiling xylene. Since the products of reaction did not crystallize, the solution in xylene was heated with aqueous alkali. Neutralization of the alkaline extract gave products with the composition RéCuHioOs but, as these were amorphous, no attempt was made to characterize them further.We have now heated 2,5-dimethyl-l, 5-hexadiene-3-yne (I) with maleic anhydride at 130°. From the reaction-mixture a crystalline product, CieHuOe, was isolated. If the two moles of maleic anhydride added one after the other in the manner of a Diels-Alder reaction, then III and IV would be the expected structures.2 The intermediate II has not been

Double Dehydro‐Diels–Alder Reactions of 1,5‐Dien‐3‐ynes

“…This transformation was first reported in 1933 by Blomquist and Marvel 3a. A series of reports by Butz and co‐workers followed, in which the scope of the reaction was examined 3b–h. Consistently low yields (2–19 %) were reported for this rare4 transformation.…”

The Diels–Alder Reaction in Steroid Synthesis

“…were made in the 1940s and 1950s, [160][161][162][163][164] and an isolated report appeared in 1996. 165 The most recent investigation of this transformation was published by Paddon-Row and Sherburn in 2009.…”

Synthesis of a Macrocycle by Application of the Wittig Reaction

“…In VI no possibility of conjugation exists and thus the absorbing chromophores of I and VI must be the same-i.e., o-disubstituted phenyl. 6 This study.…”