Cyclohept

With 7-bromobenzo[a]cyclohept-2-ene-l-one in alcohol solution, the 9,10-dihydro-8H-benzo-4,5-cyclohepta-[d]-thiazol-2-ylhydrazine (143) was obtained in 46% yield (Scheme 69) (679, 688, 689). 

Selective hydroxylation with osmium tetroxide (one equivalent in ether-pyridine at 0 ) converts (27) to a solid mixture of stereoisomeric diols (28a) which can be converted to the corresponding secondary monotoluene-sulfonate (28b) by treatment with /7-toluenesulfonyl chloride in methylene dichloride-pyridine and then by pinacol rearrangement in tetrahydrofuran-lithium perchlorate -calcium carbonate into the unconjugated cyclohepte-none (29) in 41-48 % over-all yield from (27). Mild acid-catalyzed hydrolysis of the ketal-ketone (29) removes the ketal more drastic conditions by heating at 100° in 2 hydrochloric acid for 24 hr gives the conjugated diketone (30). 

Under photochemical conditions, 12-oxatricyclo[7.2.1.02,8]dodeca-2(8),3,6,10-tetraen-5-one gives 8//-cyclohept[c/]oxepin-8-one in good yield.147 This reaction has been applied to the synthesis of a number of 2- and 2,4-substituted 8//-cyclohept[rf]oxepin-8-ones 17 147,148... 

Conjugate addition, 34-5, 51-2,53, 132, 133 Conjugate hydroxymethylation, 59-60 Copper(n) bromide, 54 Copper([) chloride, 120 Copper(n) chloride, 120 Copper(i) cyanide, 7,52, 53 Copper(i) iodide, 54 Corey s internal quench, 104 Cyanohydrin trimethylsilyl ether, 137 Cycloaddition. 34,112 Cydobutane-l,2-dione, 135 Cyclohept-2-dione, 135 Cyclohex-2-enone, 52,123 Cyclohcxa-1,3-diene, 26 Cyclohexane carboxaldehyde, 22-3,69 73,78... 

Isocyanobiphenyl (381) is converted on irradiation in cyclohexane into the cyclohept[h] indole 382317 the intramolecular adduct 383 has, without any supporting evidence, been proposed as an intermediate. 

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... 

Figure 3. Calculatedfree energy barrier for 1,2-hydride shift of cyclohept-1-enyl cation and the optimized structures (MP2/6-31 G(d)).l2b...

The cyclization of (l-azaazulen-2-yl)hydrazinomethylenemalonates (1409) in boiling te/7-butylbenzene for 30-40 min afforded l,2,5a-triaza-cyclohept[u]azulen-5-ones (1410) in 74-93% yields (88BCJ1440). Whereas the methyl derivative of 1409 (R = Me) could be cyclized in 56% yield in chloroform by treatment with silica gel at room temperature for 7 days, the ethoxycarbonyl derivative (1409, R = COOEt) could not. 

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). 

One of the very few examples of a cyclohept-2-enone undergoing photocycloaddition to a C —C double-bond system is the reaction of l,3,10-trimethyl-8-oxabicyclo[5.3.0]dec-3-ene-2,9-dione (35) with 2-trimethylsiloxybuta-1,3-diene (36) to give the desired adduct 37 in 9% yield.115... 

As it is generally accepted, formation of 1-aza-l-cyclohepte-ne in the course of the hydrogenation reaction leads to the cyclic amine We have demonstrated its ability to generate also diamine 8. 

As an extension of this highly enantioselective Michael addition of silyl nitronates with a, p-unsaturated aldehydes, the reactions with cyclic a,p-unsaturated ketones as a Michael acceptor were also tested (Scheme 9.15). Cyclohexenone and cyclohepte-none were employed as a useful Michael acceptor with various silyl nitronates in the presence of catalyst (R,R)-6c, and gave the corresponding enol silyl ethers 28 with excellent stereoselectivities [30]. 

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

CN 4,9-dihy dro-4-( 1 -methyl-4-piperidinylidene)-10H-henzoi 4,5]cycloheptal 1,2- ]thiophen-10-onc... 

A similar bidentate ligand containing a ferrocenyl bridge between two BINOL moieties was described by Reetz and co-workers. Copper-catalyzed 1,4-addition reactions of diethylzinc to cyclohex-2-enone and cyclohept-2-enone in... 

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