Application of electron spin resonance spectroscopy to studies of valence isomerization. V. Aliphatic semidiones. XXVIII. Formation of bicyclo[3.2.0]hept-2-ene-6,7-semidiones from bicyclo[3.2.0] and -[2.2.1]precursors
Abstract:27) A. de Meljere has discovered radical chlorination with tert-butyl hypochlorite to be a useful route to Introduction of chlorine at the C-1 bridgehead position of bicyclo[2.2.2]octane and blcyclo[3.3.2]decane systems to which at least one cyclopropane unit has been fused, such as trlshomobarrelene, trlshomobullvalene, and tricyclo[3.2.2.0s•4] nonane. A. de Meljere, O. Schallner, and C. Weitemeyer, Angew. Chem., Int. Ed. Engl., 11, 56 (1972), and a private communication. (28) Photochlorinatlon of norbornane… Show more
“…The assignments refer to the numbering reported below. The products 3 and 6 have been synthesized following literature procedures. , The monomers 2c , d and the trimers syn - 1c , d and anti - 1c , d are described elsewhere. 1a,c,e,h …”
Copper(I) thiophen-2-carboxylate was successfully employed in the trimerization of [2.2.1] bicyclic vic-bromotrimethyltin olefins (in their racemic composition), bearing different functionalities, to invariably obtain almost quantitative yields of the syn and anti tris-annelated benzenes. The two isomers come in different ratios, smaller than or equal to the statistical 1:3 ratio, depending on the steric hindrance opposed by the functionalities. In the case of enantiopure (3-bromo-4,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl)trimethylstannane, the 1:9 ratio found with Cu(NO(3))(2).3H(2)O increases to 1:6.
“…The assignments refer to the numbering reported below. The products 3 and 6 have been synthesized following literature procedures. , The monomers 2c , d and the trimers syn - 1c , d and anti - 1c , d are described elsewhere. 1a,c,e,h …”
Copper(I) thiophen-2-carboxylate was successfully employed in the trimerization of [2.2.1] bicyclic vic-bromotrimethyltin olefins (in their racemic composition), bearing different functionalities, to invariably obtain almost quantitative yields of the syn and anti tris-annelated benzenes. The two isomers come in different ratios, smaller than or equal to the statistical 1:3 ratio, depending on the steric hindrance opposed by the functionalities. In the case of enantiopure (3-bromo-4,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl)trimethylstannane, the 1:9 ratio found with Cu(NO(3))(2).3H(2)O increases to 1:6.
“…The properties and interconversions of Cio bicyclopolyunsaturated systems are subjects of intense interest.2 We now describe the chemistry of bicyclo [4.2.2]deca-2,4,9trien-7-one (1) and its derivatives, and the 8-ketobicyclo- [4.2.2] deca-2,4,9-trien-7-yl carbanion (2) and carbonium ion (3).…”
The synthesis of 7-oxabicyclo[2.2.1]hept-5-ene-2,3-dione (2a) and its 1-methyl derivative is described. Electrolytic reduction of 2a gives its radical anion which has a large bridgehead hydrogen coupling of 2.48 G. Using the INDO method with a MINDO/2' optimized geometry, spin densities for 2a•are calculated and partitioned into their spin polarization and spin delocalization components. Mechanisms for the interaction of the vinyl and bridgehead hydrogens in 2a•-with the unpaired electron are discussed based on the spin partitioning calculation.
“…The first report describing the detection of valence isomerization of radicals by esr appears to be that of Russell and Whittle (12) Since this earliest report, the Russell (13,14,15). Thus, treatment of ^ with base in DMSO (Scheme 1) gives a mixture of semidiones '_8a and 9a.…”
The first derivative esr spectrum of 29 bicyclo[4.2,0]octa-7-ene-2j5-semidione (1) in DMSO. 2. The first derivative esr spectrum of 32 bicyclo[4.2.0]octa-3,7-diene-2,5-dione (4o) in basic dg-DMSO after 10 minutes. 3. The first derivative esr spectrum of semi-34 quinone 6^ obtained by treating semidione 1 with air. 4. The first derivative esr spectrum recorded 36 after photolysis of a solution of semidione 1 in the esr cavity. 5. The first derivative esr spectrum (top) 42 obtained from bicyclo[4.2.0]octa-7-ene-2,5-dione (_^) in dg-DMSO; calculated spectrum (bottom) for Lorentzian line width 0.115 gauss with splitting constants from text. 6. The first derivative esr spectrum (top) of 44 semidione 69; calculated spectrum (bottom) for Lorentzian line width 0.100 gauss with splitting constants from text. 7. The first derivative esr spectrum (top) of 46 4la in basic DMSO; calculated spectrum (bottom) for Lorentzian line width 0.l4 10. The first derivative esr spectrum (top) of 59 semidione 72a; the first derivative esr spectrum (middle) of semiquinone 73a; the calculated spectrum (bottom) of semiquinone 73a for Lorentzian line width 0.25 gauss with splitting constants from Table 4. 11. The first derivative esr spectrum (top) of 6l semiquinone 73c; calculated spectrum (bottom) for Lorentzian line width 0.19 gauss with splitting constants from Table 4. 12. The first derivative esr spectrum (top) of. 63 semidione 72d; calculated spectrum (bottom) for Lorentzian line width 0.25 gauss with splitting constants from Table 4. 13. The first derivative esr spectrum (top) of 65 semiquinone 73d; calculated spectrum (bottom) for Lorentzian line width O.9O gauss with splitting constants from Table 4. 14. The first derivative esr spectrum (top) of 67 semiquinone 74e; calculated spectrum (bottom) for Lorentzian line width 0.20 gauss with splitting constants from Table 4. 15. The first derivative esr spectrum (top) of 70 semiquinone 77.; calculated spectrum (bottom) for Lorentzian line width 0.14 gauss with splitting constants from text. 16. The first derivative esr spectrum (top) of 75 semidione calculated spectrum (bottom) for Lorentzian line width O.I8 gauss with splitting constants in text. 17. The first derivative esr spectrum (top) of 78 radicals observed upon greater reduction of semidione 8I; the first derivative esr spectrum (bottom) of 2,3-dimethylsemiquinone (82). 18. The first derivative esr spectrum obtained 87 by treatment of 2,4-cyclooctadiene-l,6dione (84) with potassium t-butoxide in DMSO. vi Page 19. The first derivative esr spectrum obtained 89 from 2,4-cyclooctadiene-l,6-dione in basic DMSO under flow conditions. 20. The first derivative esr spectrum obtained 97 upon treatment of acetoxy ketone 106 with basic DMSO and traces of oxygen. 21. The first derivative esr spectrum obtained 104 by treating crude diepoxide T12 with base and DMSO under flow conditions. 22. The first derivative esr spectrum obtained 110 upon treatment of 2-cyclooctene-l,4-dione CII6) with basic DMSO. 23. Esr cell used for KOtBu/DMSO experiments...
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