The 4-alkyl-Δ1(9)-2-octalones 7–11, inclusive, prepared by conjugate addition of appropriate or ganocuprate reagents to the cross-conjugated dienones 13 and 14, were subjected to lithium–ammonia reduction. Interestingly, these reductions produced, in each case, a considerably higher proportion (13–35%) of the corresponding cis-fused 2-decalone (27–31, inclusive) as compared with that normally formed in the alkali metal – ammonia reduction of Δ1(9)-2-octalones. The results are qualitatively explained in terms of the proposals originally set forth by Robinson.

EDWARD PIERS and WYNONA M. PHILLTPS-JOHNSON. Can. J. Chem. 53, 1281Chem. 53, (1975. The annelation of the pyrrolidine enamine of cyclohexanone with (E)-2-methyl-3-hepten-5-one (7) afforded a 7:3 mixture of the octalones 12 and 13. Lithium-ammonia reduction of the former afforded the trans-fused decalone 14, whereas, in contrast, a similar reduction of 13 gave exclusively the cis-fused decalone 16. Annelation of the pyrrolidine enamine of Chydroxycyclohexanone with the unsaturated ketone 7 yielded a 7: 3 mixture of the octalones 22 and 23. The former was converted via a short, efficient synthetic sequence into (+)-cadinene dihydrochloride (30).EDWARD PIERS et WYNONA M. PHILLIPS-JOHNSON. Can. J. Chem. 53, 1281Chem. 53, (1975.L'Bnamine derivant de la pyrrolidine et de la cyclohexanone soumise a une reaction d'annelation avec la methyl-2 heptkne-3 one-5 (E) (7) conduit a un melange 7:3 des octalones 12 et 13. La reduction par le lithium dans I'ammoniac de 12 conduit a la decalone trans 14 alors qu'une reduction similaire de 13 conduit uniquement a la d h l o n e cis (16). L'knamine derivk de la The fairly large number of sesquiterpenoids which possess the basic carbon skeleton as shown in 1' have by convention been divided into four classes or subgroups, differing only in the relative stereochemistry at C,, C,, and C, (1,2). Thus, the cadinane-type (2) and bulgaranetype (3) sesquiterpenoids possess trans-fused six-membered rings and differ only in the relative stereochemical orientation of the isopropyl or related side chain. On the other hand, in the muurolanes (4) and the amorphanes (5), the decalin systems are cis-fused. Again, these two types differ only in the relative stereochemistry at C,.The four sesquiterpenoid classes mentioned above are constituted mainly of olefinic hydrocarbons and alcohols. Structurally speaking, many of the individual members of these classes are very closely related and often differ from one another only in the position of an olefinic double bond and/or in a diastereomeric sense. Because of this, it has often been difficult to separate mixtures of these types of compounds into individual components, and the structural 'The numbering system shown in structure 1 is that normally used for the cadinane and related sesquiterpenoids.and stereochemical elucidation of the cadinane and related sesquiterpenoids was, in the past, often carried out with impure materials. Consequently, the chemical literature dealing with this area contains many conflicting and erroneous reports. A classic and, perhaps, extreme example of this involves the naturally occurring olefinic alcohol 6-cadinol. Since its isolation in 1922, no fewer than seven different proposals have been put forward regarding the structure and sterochemistry of this compound, the latest (3) being that 6-cadinol is actually a muurolane derivative. Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.149.104.195 on 05/09/18For personal use only.

No abstract

Die Oktalone (III) werden aus den Dienonen (I) mit den entsprechenden Li‐dialkylcupraten (II) dargestellt.

Die Anellierung des Heptenons (I) mit dem Enamin (II) liefert ein 7 : 3‐Gemisch der Oktalone (III) und (IV) (83% Gesamtausbeute).