Dodeca-3,5-diyn

Figure 5.8 Electron micrographs of (a) right-handed helices and tubules from A-dodeca-5,7-diyne-D-galactonamide (10) and (b) braided fibers from A-dodeca-5,7-diyne-L-arabonamide (11). Reprinted with permission from Ref. 47. Copyright 1994 by the American Chemical Society.

The acyclic diyne metathesis polymerization of dodeca-2,10-diyne is catalysed by W(=CEt)(OCMe3)3 see equation 73. But-2-yne is eliminated and the product is an off-white insoluble powder with the same Tm as the polymer prepared from cyclooctyne (Section XII.B)7. 

Later Walton and his co-workers46 could show that 2 equivalents of 2-trimethyl-silyl-ethyne-magnesiumbromide couple with cyclooctatetraene dibromide to form l,12-bis(trimethylsilyl)dodeca-3,5,7,9-tetraene-l,l 1-diyne (47). 

Conjugated cis,cis-d ieney. Dihydroboration of a conjugated diyne, for example dodcca-5,7-diyne (1), with dicyclohexylborane followed by protonolysis of the organo-borane intermediate with acetic acid leads to a conjugated di.cu-diene (rw.t is-dodeca-... 

Dodeca-5,7-diyne undergoes photoreduction at one triple bond on irradiation in pentane or an alcohol (equation 26) , as does the 1,4-diyne 8, although this second dialkyne also gives rise to a cyclopentadiene product which may be formed by initial ring closure of the diyne to give a cyclopentadienyl biradical (equation 27). 

The heat of hydrogenation of octa-l,7-diyne might be expected to be twice that of 1-butyne, which is in effect one half of the molecule. The difference is only 0-6 kcal/mole. The heat of hydrogenation of hexa-l,5-diyne —139-4) compares closely with that found for octa-l,7-diyne, as might reasonably be anticipated. Also, the heat of hydrogenation of dodeca-3,9-diyne (—131 15) is close to that estimated for two moles of 3-hexyne, (ca. —131 6). In octa-l,7-diyne, hexa-l,6-diyne, and dodeca-... 

In dodeca-5,7-diyne, in which the —C C— groups are adjacent to each other, the inolecide can be considered to be stabilized by the 7r-electron eonjugation energy of the —C —C —... 

The aniline derivative 208 was obtained by cross-benzannulation of the amino-enyne 207 with dodeca-5,7-diyne (50) [64]. Cross-benzannulation of the 1,4-disubstituted enyne 209 with fte diyne 50 afforded the 1,2,3,4-tetrasubstituted benzene 210 [63]. Pentasubstituted benzene 212 can be synthesized by the coupling of the trisubstituted l-buten-3-yne 211 with the diyne 50 [63]. 

The [2+2+2+1] cycloaddition reaction of dodeca-5,10-diyn-l-al 220 carried out with [Rh(cod)Cl]2 (5 mol%) at 50°C and ambient pressure of CO in toluene gave cycloadducts 221 and 222 (65% combined yield) as well as acetyl-bis(cyclopentenyl) 223 from the [2+2+2] cycloaddition in 33% yield. Upon monitoring the reaction, it was found that fused 5-7-5 tricyclic lactone 221 was the kinetic product and the clean and complete isomerization of 221 to 222 was observed by leaving a mixture of 221 and 222 in CDCI3 in an NMR tube for 2 weeks at ambient temperature (Scheme 99). 

Scheme 11.12 S5mthesis of l-(dodeca-l,3-diyn-l-yl)-2-nitrobenzene catalyzed by 12 [34].

The most detailed investigations on chain lengths of poly(diacetylenes) were reported by Wenz and Wegner (6) on TS-12 (Dodeca-5,7-diyne-I,I2-ylene- bis (p-toluene sulfonate)), which yields a solvable polymer. It was shown that the chain length increases with conversion from about 50 repeat units in the beginning to 2000 at 10 % conversion, and then stays constant. 

The studied polymer in solution is dodeca 5,7 diyne -1,12 - ylene -bis (p-toluene sulfonate) (TS-12) with side group R=R =(CH ), OSO y 2ed by Wenz and Wegner (7). The solvent used was DMF. The optical absorption spectrum of this polymer is shown in Fig.2. The measurements have been done in cells with liquid compartment... 

NitrodiphenyIamine 4-Nitrodiphenylamine Benzenediazosulphonylbenzene Benzenediazothiobenzene trans-2-StyryIfuran Diphenylamine trans-2-StyrylpyrroIe 1,2-Dimethylnaphthalene Dodeca-2,8,10-triene-4,6-diyne... 

LAETA was obtained in situ by the reaction of lithium (0.210 g, 30.0 mmol) with absolute ethylene diamine (2.4 mL, 30 mmol) in dry THF (7.2 mL). Lithium was introduced by small portions in an argon flow. After the exothermic formation of straw-colored suspension of LAETA, dry benzene (7.2 mL) and hexane (7.2 mL) were added. The mixture was cooled to 16-18 °C, and dodeca-5,7-diyne (1.62 g, 10.0 mmol) added by syringe and the final mixture stirred for 10 min at 16-18 °C. The color of the reaction mixture changed from yellowish-gray to dark brown, indicating the formation of lithium diynide. 

Solution of dodeca-l,3-diyne (810 mg, 5.00 mmol) was reacted with 2-iodoaniIine (876 mg, 4 mmol) according to the general procedure with Pd(PPh3)2Cl2 as a catalyst. Chromatography on silica gel (hexane/CH2Cl2 2 1) afforded the 2-(dodeca-l,3-diynyl)aniline (961 mg, 95%) as an oil 0.22 (hexanes/CH2Cl2 4 l). 

Dodeca-5,7-diyne (1.62 g, 10.0 mmol) was used to obtain dodeca-l,3-diyne that was reacted with 1,2,4,5-tetraiodobenzene (1.164 g, 2.00 mmol) using Procedure A. Chromatography on silica gel (hexane) afforded the tetrayne (1.34 g, 93%) as a solid mp 45-46 °C R 0.5 (hexane). ... 

A Strategy of cyclopropenylation of oligocycles. The ene-diynes 2.305 contain methylencyclopropenyl blocks that can be readily attacked at the three-membered ring junction with the double bond in the Co(I)-catalyzed [2+2+2] cocyclization. This results in the formation of polycyclic compounds 2.306 containing condensed and spiro-connected cyclopropane rings, tricyclo[7.3.0.0.(2.6)]dodeca-l,6-diene (l,2,3,3a,4,6,7,8-octahydro-i2s-indacene) in yields from 31% to 94% (Scheme 2.101) [106],... 

The first attempt to construct a condensed core was a unique silicon-initiated (CO-SiCaT) reaction of carbonylated carbotricyclization of enediynes 2.314 [154, 161]. The 5-7-5 fused tricyclic products can be produced from the same type enediynes and CO through also by the rhodium-catalyzed intramolecular [2+2+2+1] cycloaddition [154, 160]. Reaction of dodeca-ll-ene-l,6-diyne 2.314 or heteroatomic analogues with a hydrosilane catalyzed by Rh(acac)(CO)2 at ambient temperature and pressure affords the corresponding fused 5-7-5 tricyclic system with a seven-membered lactone ring, 5-oxo-l,3a,4,5,7,9-hexahydro-6H-cyclopenta[e]azulenes 2.315 or related heteroanalogs in a yield from good to excellent (50-98%) (Scheme 2.104) [154]. 

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