Bicyclo decene

Hydroxy-tetralin bildet in entsprechender Reaktion 60% d.Th. 2-Oxo-dekalin (I) neben 30% d.Th. 4-Oxo-bicyclo[4.4.0]decen-(2) (II)1 ... 

IOf)-Hydroxy-7-oxo-2f3-carboxy-trans-bicyclo [4.4.0]decen-(3)-lacton y... 

Zur Reduktion von 3,7-Dioxo-6/3-methyl-2-(2-carboxy-athyl)-bicyclo[4.4.0]decen-( 1) s.S. 764. 

Cyclic stannanes can be generated by reaction of stannylenes with alkynes112. For example, bis[bis(trimethylsilyl)methyl]tin reacts with cyclooctyne to provide A1,18-9,10-(distanna-9,9,10,10-tetrakis[bis(trimethylsilyl)methyl])bicyclo[6,2,0]-decene, 69. This reaction is a typical oxidative addition on stannylenes. 

Thus far, rhodium(i) complexes are the most general, efficient, and selective catalysts, uniquely enabling [5 + 21-cycloadditions of tethered alkyne-VCPs, alkene-VCPs, and allene-VCPs. For example, when tethered alkene-VCP 7a (Equation (2)) is treated with [(cod)Rh(CioH8)]SbF6, the bicyclo[5.3.0]decene is produced in 96% yield. 

The first example of an enantioselective [5 + 2]-cycloaddition was reported for the tethered alkene-VCP 7a, which upon treatment with a chiral rhodium complex afforded the m-fused bicyclo[5.3.0]decene 8a in 80% yield and 63% enantiomeric excess (ee) (Equation (6)).39 A later study found that when a 2,2-bis(diphenyl-phosphanyl)-l,l-binaphthyl (BINAP)-modified rhodium(l) catalyst is used, good to excellent ee s and yields are achieved with a variety of substrates (Equation (7)).40... 

An interesting approach to carbobicyclic polyhydroxylated compounds was proposed by Jarosz.43 It was based on a Lewis acid transformation of sugar allyltins 82 into dieno-aldehydes 83 with the fi-geometry across the internal double bond exclusively. The Wittig-type reaction of 83 afforded a triene, which underwent cyclization under high pressure, providing derivatives of bicyclo[4.3.0]nonane 84. Alternatively, dienoaldehyde 83 was converted into the phosphonate 85, which afforded the bicyclo[4.4.0]-decene derivatives (86) upon reaction with an aldehyde and simultaneous cyclization of the resulting triene.43 (Fig. 29). 

On heating above 200 °C, 2,5-bis(trimethylsiloxy)tricyclo[4.4.0.02 5]decan-7-ones undergo a [2 4- 2] cycloreversion to form either 1,2-divinylcyclohexanes or 1,5-bis(trimethylsiloxy)cyclodeca-1,5-dienes. These are not stable at elevated temperatures and rearrange. After aqueous acidic workup, bicyclo[5.3.0]decene-2,5-diones 13 are isolated.45... 

Exercise 12-30 How could you phrase Bredt s rule so it could distinguish between the lack of stability of 16 and the stability of bicyclo[5.5.0]-1,2-decene, both compounds having a double-bonded carbon at a ring junction ... 

Majetich reports a general intramolecular Lewis acid allylation protocol for the synthesis of bicy-clo[5.4.0]undecen-3-ones (168) and bicyclo[4.4.0]decen-3-ones (170), which are 1,6-addition products (Scheme 27). The same precursors, (167) and (169), when submitted to the fluoride ion cyclization protocol, also afford 1,2- and 1,4-addition products.73 Typically, ethylaluminum dichloride, a proton sponge Lewis acid, is used in order to minimize adventitious protonic desilylation. Other 0,y-unsatu-rated silanes also undergo similar intramolecular Lewis acid catalyzed additions for example, the si-lylpropargylic enones (171) undergo intramolecular cyclization to the allenylspiro system (172).74... 

The ability of a methanesulphonate substituent to function as a leaving group (compare equation 124, Section VI.E.2) in an intermediate cyclopropane permits transformation of a bicyclo[4.4,0]decene derivative into a compound with a hexahydroazulene skeleton having potential for sesquiterpene synthesis(equation 76). 

Reaction of dienoaldehyde with the stabilized Wittig reagent(s) provided a triene 88, which upon high-pressure Diels-Alder cyclization furnished bicyclo[4.3.0]nonene [78]. Alternatively the aldehyde S7-E was converted into the methyl ester 89, which reacted with the dimethyl methylphosphonate anion affording the phosphonate 90. Reaction of the latter with aldehydes under mild PTC conditions yielded a (regioisomeric to the previous one) triene 91, which cyclized spontaneously to bicyclo[4.4.0]decene (O Scheme 37) [79]. 

Am Bicyclo[4.4.0]decadien-(1,3) laufen bcidc Reaktionstypen gleiehzeitig ab1, so daB Tricyclo[4.4.0.01 i]decen-(2) und l-Butadien-(l,3)-yl-cyclohexen gebildet werden ... 

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