Cyclooctadienes monoepoxides

Ikegami has devised an interesting approach based upon 1,3-cyclooctadiene monoepoxide as starting material (Scheme LX) Transannular cyclization, Sharpless epoxidation, and silylation leads to 638 which is opened with reasonable regioselec-tivity upon reaction with l,3-bis(methylthio)allyllithium. Once aldehyde 639 had been accessed, -amyllithium addition was found to be stereoselective, perhaps because of the location of the te -butyldimethylsilyloxy group. Nevertheless, 640 is ultimately produced in low overall yield. This situation is rectified in part by the initial formation of 641 and eventual decarboxylative elimination of 642 to arrive at 643. An additional improvement has appeared in the form of a 1,2-carbonyl transposition sequence which successfully transforms 641 into 644... 

In view of the analogous behavior of 1,3-cyclooctadiene monoepoxide (52), it appears that the double bond in this molecule has little effect on the course of the reaction.88 When the tram epoxide 53 is involved, the hydroxyl group in the bi-cyclic alcohol is oriented exo and a reasonable amount of ring contracted aldehyde can be isolated.87 ... 

Attempts to induce transannular bonding in 1,5-cyclooctadiene monoepoxide have been moderately successful, but under acidic conditions only.91,92 ... 

Transannular hydride shifts, first detected by Cope and coworkers in solvolyses of cyclooctene oxide, have subsequently been found in a number of related systems, e.g. cyclooctadiene monoepoxides, CA o-bicyclo[3.3.1 ]non-2-ene epoxide and l-oxaspiro[2.6]nonane. In general these reactions do not involve skeletal rearrangements, and they will not be discussed in detail. 

Rearrangements are also observed during halojluonnanons with cyclic medium ring dienes [70, 93] (equations 4 and 5) and with the monoepoxide of 1,5-cyclooctadiene [94] (equation 6) during halofluonnations Again, there are differences in product mixture with apparently minor variations in reagents (equation 4)... 

Epoxidation of olefins. Sheng and Zajacek1 have worked out a procedure for the efficient monoepoxidation of 1,5-cyclooctadiene in which a mixture of 1 mole of the diene, 0,5 mole of 92% /-butyl hydroperoxide, and 0.1 g. of molybdenum hexacarbonyl is placed in a 500-mi. pendaclave (a cylindrical stainless steel pressure reactor sold by Pressure Products Industries, Inc., Hatboro, Penna. 19040). The reaction... 

Bis[dicarbonylchlororhodium(I)] and bis[(l,5-cyclooctadiene)chlororhodium(I)], Epoxide opening. The monoepoxide of a diene is regioselectively attacked by nucleophile (ArNHR, ROH) at the allylic position using [Rh(CO)2Cl]2 as catalyst, affording anil-1,2-amino alcohols and alkoxy alcohols. The results are apparently complementary to those obtained from the Pd-catalyzed process. 

The flash vacuum pyrolysis of the monoepoxide of 1,3-cyclooctadiene (362) gave, in a clean and... 

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