Bicyclo deca-2,6-diene

The recent upsurge of interest in systems of theoretical interest demands practical syntheses of several important compounds. These are BICYCLO[2.l.0]PENT-2-ENE, BENZOCYCLOPROPENE, 1,6-OXIDO[10]ANNULENE, and others. ewdo-TRICYCLO[4.4.0.02 5]-DECA-3,8-DIENE-7,10-DIONE is utilized as a model for the use of CYCLOBUTADIENE IN SYNTHESIS, and a stable monomeric ketene, icri-BUTYLCYANOKETENE offers opportunities for further studies of this interesting species. 

Chelate complexes of the type [PdX2(diene)] (X = Cl, Br) are readily formed by the dienes hexa-1,5-diene (124), bicyclo 2,2,lJhepta-2,5-diene (1, 7) tricyclo[4,2,2,0]-deca-triene and -diene derivatives (10), cyclo-octa-1,5-diene and dicyclopentadiene, but not dipentene (43). These may be converted to complexes of the types [Pd2X2(dieneOR)2] and [PdCl(dieneOR)-(amine)] (R = alkyl) (43), and their properties indicate that they have similar structures to the platinum complexes (XXXI) and (XXXIII). 

Rhodium(I)-catalysed Pauson-Khand reaction of allenynes has been shown to be applicable for constructing azabicyclo[5.3.0]decadienone and oxabicyclo[5.3.0] decadienone frameworks. The 10-monosubstituted-bicyclo[5.3.0] deca-l,7-dien-9-one ring system has been prepared by the rhodium(I)-catalysed Pauson-Khand reaction of allenynes under 10 atm of CO (Scheme 86).129... 

IO-Aza-tricydo 3.3.2.02,8]deca-3,6-dien 9-Oxo- EI7b, 1219 (10-Oxo-9-aza-bicyclo[4.2.2]deca-2,4,7-trien/hv)... 

Benzo-l-aza-6-bora-bicyclo [4.4.0]deca-2,4-dien XIII/3b, 47... 

Bicyclo[4.5]deca-2,6-dien 3,6-Dimethyl-1-oxo- E19a, 221 (3-En-CO-Cl + In) Cydobuten 2(or 3)-(Dimethyl-phenyl-silyl)- 1-oxo- E17e, 284 (Keten -f- CH2N2)... 

Eisen(II) (2-4- jJ-7-Hydroxy-4-dehydro-bicyclo[3.3.2]deca-2,9-dien-6-yl)-tricarbonyl- Xlll/9a, 252... 

Bicyclo 4.4.0]deca-l,4-dien 2-Meth-oxycarbonyl-6-methyl-3-oxo-IV/la, 355... 

Surprisingly, bicyclo[4.2.2]deca-2.4-dien-7-one (9) undergoes either syn or anti cycloaddition to the carbonyl group1. 

MO calculations have been carried out on the isomerization of cyclopropane to propene, and the MNDO method has been used to study the reaction pathway and to optimize the structure of reactant, transition structure, and product of the ring opening reaction of bicyclo[1.1.0]butane. Various methods have been employed to estimate the rate constants for ring opening of the 2-cyclopropyl-2-propyl radical. 1-Acceptor-1-sulfenyl-substituted 2-vinylcyclopropanes of the type (430) have been found to afford 6-sulfenyl-a,jS y, -unsaturated carboxylic esters and nitriles (431) upon treatment with acid, by a process which involves C(l)—C(2) bond fission and a novel 1,5-sulfenyl rearrangement (see Scheme 110). It has been shown that the benzophenone-sensitized photolysis of vinyl norcaradiene derivatives, such as 5-(2-methylprop-l-enyl)-3-oxatricyclo[4.4.0.0 ]deca-7,9-dien-4-ones (432), results in the regioselective cleavage of only one of the cyclopropyl c-bonds to afford isochroman-3-one derivatives (433). It has been reported that the major product obtained from the reaction of structurally diverse a-diazo ketones with an electron-rich alkene in the... 

Later work by Parker et a/.demonstrated that extended treatment of humulene with aqueous sulfuric acid in acetone led largely to the bicyclo[5.3.0]deca-2,10-diene (115), via initial formation of humulol... 

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