Cyclodecenes

Similar fragmentations to produce S-cyclodecen-l-ones and 1,6-cyclodecadienes have employed l-tosyloxy-4a-decalols and 5-mesyloxy-l-decalyl boranes as educts. The ringfusing carbon-carbon bond was smoothly cleaved and new n-bonds were thereby formed in the macrocycle (P.S. Wharton, 1965 J.A. Marshall, 1966). The mechanism of these reactions is probably E2, and the positions of the leaving groups determine the stereochemistry of the olefinic product. 

The reduction of medium-size cycloalkynes, however, always yields considerable amounts of the less strained cis-cycloalkenes (A.C. Cope, 1960 A M. Svoboda, 1965). Cyclo-decyne, for example, is reduced almost exclusively to cis-cyclodecene. 

Cyclodecanediol has been prepared by the hydrogenation of sebacoin in the presence of Raney nickel or platinum, by the reduction of sebacoin with aluminum isopropoxide or lithium aluminum hydride, and by the oxidation of cyclodecene with osmium tetroxide and pyridine. ... 

E-Cyclooctene is also significantly straine4 but less so than -cycloheptene. As the ring size is increased, the amount of strain decreases. The. E-isomers of both cyclononene and cyclodecene are less stable than the corresponding Z-isomers, but for cycloundecene and cyclododecene, the E-isomers are the more stable. Table 3.10 gives data concerning the relative stability of the C7 through C12 cycloalkenes. 

Based on the successful series of transformations summarized in Scheme 1, Schreiber and Santini developed an efficient and elegant synthesis of periplanone B (1),8 the potent sex pheromone of the American cockroach, Periplaneta americana. This work constitutes the second total synthesis of periplanone B, and it was reported approximately five years after the landmark periplanone B synthesis by W.C. Still9 (see Chapter 13). As in the first synthesis by Still, Schreiber s approach to periplanone B takes full advantage of the facility with which functionalized 5-cyclodecen-l-one systems can be constructed via anionic oxy-Cope rearrangements of readily available divinylcyclohexanols.5 7 In addition, both syntheses of periplanone B masterfully use the conformational preferences of cyclo-decanoid frameworks to control the stereo- and regiochemical course of reactions carried out on the periphery of such ring systems.10... 

Cyclodecin ergibt nach Deuteroborierung mit Hexadeutero-diboran und Deuterolyse mit Essigsaure-O-D 43% deuteriertes Produkt, das 81% cis-1,2-Dideutero-cyclodecen enthalt7 ... 

Another report by Rychnovsky et al. explored the potential of chirality transfer in the transannular cyclization of cyclodecene 45 [42], They proposed a radical deoxygenation of 45, which produces an intermediate cyclodecenyl radical that can cyclize in a 5-exo fashion to yield 5,7-fused bicycle 48 (Scheme 13). The potential for the optically enriched radical precursor 45 to undergo enantioselective cyclization is dependent on the rate of transannular cyclization. That is, if the radical generated from optically pure... 

A systematic study has confirmed the low activity of EHs toward cycloalkene oxides (1,2-epoxycycloalkanes, 10.123) [184], In the presence of mouse liver microsomal EH, activity was very low for cyclopentene oxide and cyclohexene oxide (10.123, n = 1 and 2, respectively), highest for cyclo-heptene oxide (10.123, n = 3), and decreased sharply for cyclooctene oxide (10.123, n = 4) and higher homologues. Mouse liver cytosolic EH showed a different structure-activity relationship in that the highest activity involved cyclodecene oxide (10.123, n = 6). With the exception of cyclohexene oxide, which exhibited an IC50 value toward microsomal EH in the p.M range, cycloalkene oxides were also very weak inhibitors of both microsomal and cytosolic EH. 

The same allylic species can be formed from the related 1,3-diene and indeed cw,ci5-l,3-cyclodecadiene yields at least 38% tmns-cyclodecene although the saturation of one double bond which did not involve its neighbor should obviously yield the more stable cis isomer. The result implies that the allylic intermediate, which would be formed initially in the cis,cis conformation, has time to rearrange on the siurface to its more stable cis,trans configuration before it reacts further with hydrogen. The possibility that the ct ,cts-l,3-cyclodecadiene isomerizes first to the less stable cis,trans-diene was discounted. The rearrangement of the allylic intermediate could be accomplished via a o-bonded complex, as indicated on page 142 of Section III,C. 

The conversion of the m-monoolefin to its silver nitrate complex 1 was accomplished by adding 1.66 g. (0.010 mole) of the distilled reaction product to a solution of 1.70 g. (0.010 mole) of silver nitrate in 50 ml. of boiling methanol. The resulting solution, when cooled, deposited the complex as white needles, m.p. 79° dec. recrystallization from methanol separated 1.0 g. of the complex, m.p. 80° dec. After this complex had been partitioned between water and ether, the ether phase was separated, dried over magnesium sulfate, and concentrated. Distillation of the residual liquid in a short path still separated 0.45 g. of the pure (Note 6) cfs-cyclodecene, b.p. 70° (1.0 mm.), n B 1.4852. 

Although an unsuccessful optical resolution21 of ( )-cyclodecene suggested its optical instability, Robert s dynamic NMR studies 22) of the racemization process in deuterated ( )-cycloalkenes 13 succeeded in providing a t1/2 value of 104 sec (room temperature). This optical instability, found in the parent compound, could explain Westen s fruitless attempt to prepare the chiral ( )-cyclodecenone 16 from the (+)-methanesulfonate 15 23). 

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