1.6- Cyclodecadiene synthesis

Immediately after the discovery of the cyclodecadiene synthesis by the co-oligomerization of butadiene and ethylene, the question of whether other unsaturated systems could be used in place of ethylene was investigated. Of the many variations on this theme which have been studied (92, 93), we will limit ourselves to discussing the co-oligomerization of 2-butyne, since this system became a model for all the other combinations. 

The intramolecular Hiyama reaction is excellently suited for the construction of carbocyclic and heterocyclic ring systems of different size. In most examples, problems of induced diastereoselectivity are involved (Sections 1.3.3.3.9.2.2. and D.2.3.). In the total synthesis of the antitumor germacranolide ( )-costunolide from ( ,.E)-farnesol, the correctly substituted ( , )-cyclodecadiene moiety was constructed by an intramolecular Hiyama reaction22. 

In highly substituted cyclodecadienes. Cope equilibria do not always lie totally on the side of the divinylcyclohexane. Linderedactone" and isolinderalactone, for example, exist in a 1 1 ratio at 160 °C (equation 72) the equilibrium has allowed a synthesis" of linderalactone through its isomer. Aldehyde... 

Transannular cyclizations of cyclodecadiene monoepoxides have been studied in exhaustive detail, particularly amongst natural germacranolides, because of their relevance to biogenetic models for the synthesis of eudesmane- and guaiane-type sesquiterpenes. " A full discussion of this topic is beyond the scope of this chapter, but the examples collected in equations (54-64) provide the reader with an in-... 

The full report on the synthesis of the hexano-bridged oxepin (140) has now appeared and further work has been reported on its oxidative cleavage to give cyclodecenes and cyclodecadienes, and on some addition reactions. The structure of the dehydration product of 2,6-di-t-butyl-4-phenyl-l-(p-tolyl)cyclohexa-2,5-diene-l,4-diol, previously postulated as a fully unsaturated oxepin, has now been confirmed by X-ray analysis. ... 

Another interesting procedure for the synthesis of pure cycloolefins, developed by Kupper and Streck [25], starts from a cyclodiene. In this method, cyclo-pentene is obtained through metathesis scission of 1,6-cyclodecadiene under the influence of WClg-based catalysts ... 

The silver-nitrate-catalysed cyclopropyl-allyl rearrangement of (451) has been used in the preparation of benzazocines and, by ring expansion of (452) with silver acetate-acetic acid, the two substituted trflns,cis-cyclonona-dienes have been made. The trans,trflns-cyclodecadienes (454), which are involved in a synthesis of cyclodeca l,6-diyne-3,8-diol, have been prepared by... 

The formation of cycloolefins from allylic dihalides (i) and nickel carbonyl has previously been shown to provide an unusually efficient route for the formation of large rings, and is exemplified in the synthesis of humulene (11-membered ring formation) by E. J. Corey and E. Hamanaka, J. Amer. Chem. Soc., 89, 2758 (1967). However, in the case of 1,10-dibromo-2,8-decadiene (i, n = 4), the predominant course of cyclization was formation of the 6-membered ring structure (ii) by 3,8 coupling rather than the expected 1,5-cyclodecadiene (iii), E. J. Corey and E. K. W. Watt, J. Amer. Chem. Soc., 89, 2757 (1967). 

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