Dispiro deca-4,9-diene

A variety of other highly-strained electron-rich donors also form colored complexes (similar to homobenzvalene) with various electron acceptors, which readily undergo thermal cycloadditions (with concomitant bleaching of the color).209 For example, Tsuji et al.210 reported that dispiro[2.2.2.2]deca-4,9-diene (DDD), with an unusually low ionization potential of 7.5 eV,211 readily forms a colored charge-transfer complex with tetracyanoquinodimethane (TCNQ). The [DDD, TCNQ] charge-transfer complex undergoes a thermal cycloaddition to [3,3]paracyclophane in excellent yield, i.e.,... 

Ring cleavage occurs when ( y4-dispiro[2.0.2.4]deca-7,9-diene)Fe(CO)3 is treated with tetrafluoroboric acid, to give after exchange with PF6" a stable / -complex cation (equation 146) which, upon further reaction with NaN(SiMe3)2 in MeCN/THF, afforded the... 

Various miscellaneous dialkylidene- and dialkenylcyclopropanes have been prepared by the double elimination of dihalides. Generally, potassium hydroxide or /ert-butoxide is used as the base. For example, dispiro[2.2.2.2]deca-4,9-diene (2) was prepared by passing the corresponding dichloride 1 through a column heated to 100-120°C containing potassium ferr-butox-ide supported on silica. The yield of product purified by gas chromatography was 48%. ... 

Methylenecyclopropanes undergo a variety of [2 + 3] cycloadditions (1,3-dipolar cycloadditions) across the double bond. Examples of the addition of diradicals are some of the dimerization reactions of methylenecyclopropane vide infra). Small quantities (< 5%) of an addition product of a 1,3-diradical to methylenecyclopropane with preservation of the three-membered ring were isolated from the thermal reaction of dispiro[2.2.2.2]deca-4,9-diene with methylenecyclopropane. ... 

The 1,9-zwitterion 9, formed by the reaction of dispiro[2.0.2.4]deca-7,9-diene (8) with TCNE, is so reactive that it incorporates cyclic ethers, such as tetrahydrofuran, oxetane and oxirane, with ring opening into the macrocyclic product. ... 

Clearly, additional activation of the cyclopropane cr-bonds is necessary. Aromatization of the cyclohexadiene ring is the driving force in the bishomodiene cycloadditions of dispiro[2.0.2.4]-deca-7,9-diene (1), while additional strain and Tt-donor activation are operative in the qua-dricyclane (2) and 3-heteraquadricyclane (3) systems. 

Thermolysis of dispiro[2.2.2.2]deca-4,9-diene (7) at 190°C in 2-methoxyethyl ether (diglyme) or triethylene glycol dimethyl ether (triglyme) gave a 70% yield of 1,4-diethylbenzene (10). ° From a study of the CIDNP effects shown by the product and reactant, two diradical intermediates 8 and 9 were postulated. 

The fully rearranged diradical 9 from dispiro[2.2.2.2]deca-4,9-diene (7) was also successfully trapped by styrene, and substituted styrenes 13, to produce [2.4]paracyclophanes 14 in an analogous series of thermolyses carried out in the presence of rer/-butyl alcohol. " ... 

Thermal decomposition of dispiro[2.2.2.2]deca-4,9-diene, in the presence of conjugated dienes or styrenes, yielded [8]paracyclophanes, or [4.4]paracyclophanes, respectively. The paracyclophanes were formed when the fully ring-opened diradical intermediate from the dispiro compound was trapped by the alkenes in a macrocyclization process (see Section 2.4.1.5.2.8.). 

On the other hand, Nishida and his associates (30, 31) made a [3.3]paracyclophane derivative from the reaction of dispiro-[2.2.2.2]deca-4,9-diene and TCNQ without the high dilution technique and moreover in high yield. They showed the presence of a zwitter ionic intermediate. The reaction suggests us that if such an electronic attractive force is existed in an intermediate, even the strained [3.3]paracyclophane skeleton can be rather easily prepared. 

TCNE undergoes an unusual cycloaddition reaction with dispiro[4.2.2.0] deca-7,9-diene (6) in THF at 0°. The structure of the adduct (7) has been elucidated by X-ray analysis. ... 

Disodium tetracarbonylfcrratc, 550-552 Disodium tetrachloropalladate, 45 Dispiro [ 2.0.2,4] deca-7,9-diene, 568 Disulfides, 231-232, 563, 586 N,N-Disulfonimides, 531 Dithallous ethylene glycolate, 186 Dithia[3.3J metacyclophanes, 85... 

Conformation a is fbced in spiro[2.4]hept-4-ene (J), homofulvene (6), the bull-valene derivatives 7 to 9, semibullvalene (10), barbaralene (II), and dispiro[2.2.2]-deca-4,9-diene (72). Homotropilidene (7i) is an example for conformation b. 

Dispiro[2.2.2.2]deca-4,9-diene and Dispiro[2.0.2.4]deca-7,9-diene 356... 

In a related case, de Meijere found that dispiro[2.0.2.4]deca-7,9-diene gives o-ethylstyrene and tetralin in an 87 13 ratio upon heating at I40°C with a half-life of 29 min (Scheme 11.65). ... 

The pyrolysis of dispiro[2.0.2.4]deca-1,5-diene gives tetralin, benzocyclobutene, and styrene in a 2 2 1 ratio, respectively, along with traces of 4-ethynylspiro[2.5]-hept-l-ene (Scheme 11.66). ... 

The addition of dichloroketen to (343 n = 1 R = H) is anomalous compared with that of N-chlorosulphonylisocyanate (Scheme 52), " and the reaction of dispiro[2,0,2,4]deca-7,9-diene with tcne and THF is even more unusual. ... 

The Simmons-Smith reaction has been used with several methylenecyclo-alkanes to give spiro[2,ra] alkanes. Cyclopropanation of (53) is the first stage of a preparation of dispiro[2,2,2,2]deca-4,9-diene (see p. 151), and the tetra-spiro-compound (54 n = 5) may be made in high yield by a similar reaction... 

Cyclophanes prepared by cycloaddition reactions include the tetra-substituted [2.2]paracyclophanes (435) and the [4.2]paracyclophanes (436), these being obtained by cycloaddition of dispiro[2.2.2.2]deca-4,9-diene (437) with styrene derivatives (438), with homolytic cleavage of the cyclopropane rings. 

See, for example, de Meijere, A., Kaufmann, D., and Erden, I., Photooxidation of dispiro[2.0.2.4] deca-7,9-diene and its analogs synthesis and properties of new nonenoHzable cyclo-hex-2-ene-l,4-diones. Tetrahedron, 42, 6487,1986. 

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