Undeca-3,8-dienes, synthesis

The first step in this preparation, the epoxidation of 1,4,5,8-tetra-hydronaphthalene, exemplifies the well-known selectivity exerted by peracids in their reaction with alkenes possessing double bonds that differ in the degree of alkyl substitution.12 As regards the method of aromatization employed in the conversion of ll-oxatricyclo[4.4.1.01-6]-undeca-3,8-diene to l,6-oxido[10]annulene, the two-step bromination-dehydrobromination sequence is given preference to the one-step DDQ-dehydrogenation, which was advantageously applied in the synthesis of l,6-metliano[10]annulene,2,9 since it affords the product in higher yield and purity. 

It has been established that the course of the sequential pericyclic reaction of cyclopentadienones with acyclic conjugated alkadienes depends on the reaction temperature, thermal treatment at low temperatures affording 3a,4,7,7a-tetrahydroinden-l-one derivatives by way of a Cope rearrangement (see Scheme 38). Roman et al have developed an efficient stereoselective synthesis of enantiomerically pure i-nitrotricyclo[5.2.2.0 ]undeca-3,8-dienes via a tandem consecutive asymmetric Diels-Alder-Cope rearrangement (see Scheme 39). Adducts... 

Gilbert A, Cosstick KB. ll-Cyano-4-oxatricyclo[7.2.0.03 7]undeca-2,10-diene. In Mattay J, Griesbeck AG, eds. Photochemical Key Steps in Organic Synthesis. Weinheim VCH, 1994 175-176. 

Dehydrogenatioa, Vogel ei al. present procedures for the synthesis of tricyclo-[4.4.1.0 ]undeca-3,8-diene (C) by reduction of naphthalene to isotetralin (A), addition of dichlorocarbene (B), and dechlorination (C). Dehydrogenation with DDQ in... 

Intramolecular meta photocycloaddition of 2-MeC6H4CH2CMe2CH2CH CH2 provides appropriate tetracyclic precursors from which the key tricyclic framework required for the synthesis of ( )-ceratopicanol can be obtained.This constitutes an example of a typical holosynthon. N-Benzoyl-N-benzylcinnama-mides and related compounds will photocycloadd in the presence of benzil to give 3-azatricyclo[5.2.2.0 ]undeca-8,10-dien-4-ones with high stereoselectivity, and this constitutes the first example of a photochemical [4+2] cycloaddition of an enone to a benzene ring. For example, irradiation of (60 R = H, alkyl, phenyl = H, Me X = H, OMe, Cl, etc.) gives (61 same R, R, X). 

Starting from (Z)-undeca-l,5-dien-3-ol a biogenetic-type synthesis of (+ )-dictyopterene A was achieved using the homoallyl-cyclopropyl rearrangement as the key step for cyclopropyl formation. Solvolysis of (Z)-3-mesyloxyundeca-l,5-diene under a variety of conditions failed to give cyclopropylmethyl compounds due to the presence of the terminal double bond. In contrast, (Z)-3-mesyloxy-l-(phenylthio)undeca-5-ene (3) afforded a mixture of epimeric cyclopropyl-methanols 4 in 91 % yield. Appropriate functional group transformation eventually leads to the desired dictyopterene A. 

This enhanced reactivity in rigid systems was also demonstrated by the facile reaction of tricyclo[5.3.1.0 ]undeca-2,5-diene with maleic anhydride to give 15, used as the key step in the synthesis of the iceane analogs homoiceane and 3,12-cycloiceane. ... 

Undeca-l,2-diene treated sequentially with equimolecular quantities of -butyl-lithium and -propyl iodide in tetrahydrofuran -> tetradeca-4,5-diene. Y 96% purity 95%. F. e., also synthesis of allenes from bromoallenes, s. G. Linstrumelle and D. Midielot, Chem. Commun. 1975, 561 alkylation of allenes via Li-diallyl-cuprates cf. Tetrah. Let. 1976, 275. 

Silver nitrate-catalysed rearrangements in methanol of dibromocyclopropyl propellanes have been examined. For example, (80 R = Br) gave a mixture of the corresponding methyl ketal (80 R = OMe) and bicyclo[5,4,0]undec-l(7)-en-2-one, together with minor products. One step in a reported synthesis of 1,7-methano-[12]annulene involved addition of dibromocarbene to tricyclo[4,4,l,0 ]undeca-3,8-diene (81) followed by silver acetate-catalysed ring-opening of the resultant bis-dibromocarbene adduct to give a mixture of isomeric acetates. ... 

Although less frequently than with polyesters, it is possible to produce other polymers from ADMET polymerisation. Mecking and co-workers [44] described the synthesis of polyacetals and polycarbonates (PC) with a sparse and systematically varied density of functional groups generated by ADMET copolymerisation of unfunctionalised undeca-1,10-diene with bis(undec-10-en-l-yloxy)methane or di(undec-lO-en-l-yl) carbonate, followed by exhaustive hydrogenation (Scheme 5.10). 

Niwa, H., Yoshida, Y, Hasegawa, T., and Yamada, K. (1985) Total synthesis of ( )-(Z)-9-(bromomethylene)-l,5,5-trimethylspiro[5.5] undeca-l,7-dien-3-one, a brominated sesqui-terpene of chamigrane type. Chem. Lett., 14,1687-1688. 

The seven-membered-ring disulphide (77) has been isolated from a species of Hawaiian alga " and the structure confirmed by the following synthesis the reaction of 2-nonenal with vinyl-lithium followed by oxidation with DDQ gave the undeca-l,4-dien-3-one, which readily added thiolacetic acid to each double bond. The dithiol ester thus produced was hydrolysed to the dithiol with methanol-HCl. Cyclization to (77) was effected with iodine in pyridine. A dimeric fourteen-membered-ring tetrasulphide was obtained as by-product. 

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