Cyclohept l-

Primary vinyl iodonium compounds (1, R3 = H) are readily prepared as stable salts, but secondary analogs (1, R3 = alkyl) cannot be isolated without the presence of electron-accepting moieties. Cyclopent-l-enyl iodonium salt is very stable and poorly reactive toward bases and nucleophiles, while cyclohept-l-enyl... 

A series of cyclohept[l,2-A5,4-3 ]bisindole derivatives have been obtained by the reaction of l,2-bis(17/-indol-2-yl)-ethane 208 with carboxylic acids, orthoesters, aldehydes, or ketones under acid conditions (Equation 138 Table 17) <2000T1911>. In the case of the reaction with TEA, the major product is the fully conjugated derivative (Section 10.21.5.1.3). 

Figure 3. Calculatedfree energy barrier for I,2 hydride shift of cyclohept-l-enyl cation and the optimized structures (MP2/6-3J G(d))J ...

Larger ring polyhalocycloalkanones behave in a predicatable fashion. Thus 2,8-dibromocyclooctanone yields cyclohept-l-enecarboxylic acid in 96% yield when treated with aqueous NaOH, and 2,2,8-tribro-... 

CycIohept [Pg.769]

Rings with one heteroatom are [6]-fused unless otherwise stated. h The numbering used is that of bicyclic systems (295, 296). Tropolones. d- e s Also antistrychnine, antiallergic, or cardiovascular agents, respectively. 8 See 90H(31)677 94JHC1557. h 67/-Benzo[5,6]cyclohept[l, 2,3-cd]indoline-1,6-diones. 1 See 91MI1. 

On irradiation, 2-(cycloheptylidene)cycloheptanone isomerizes to 2-(cyclohept-l-enyl)cycloheptanone, which on further irradiation cyclizes to a mixture of all four possible isomers of the oxetan (204). An analogous mixture of oxetans was obtained by irradiation of 2-(cyclo-oct-l-enyl)cyclo-octanone. ... 

A variety of intramolecular photoadditions have been studied. jffy-Un-saturated ketones usually undergo 1,3- and 1,2-acyl shifts on irradiation however, in the cases of 2-cyclohept-l-enylcycloheptanone (18) and 2-cyclo-oct-l-enylcyclo-octanone (19), oxetans are the major products. An oxetan (21) was also obtained from direct photolysis of ( )-retro-y-ionone (20) although in this case photoaddition of the ketone took place across the 4,5 positions. The (Z)-isomer (22) gave a cyclobutene through... 

Irradiation of benzyl cyclohept-l-enyl ketone through pyrex in the presence of BF3-etherate gave (311) via a singlet state process. y,5-Epoxyeucarvone (312) gave the rearranged products 8-oxo-l,4,4,-trimethylbicyclo[3,2,l]oct-6-en-2-one (46%) and... 

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