Deca synthesis

CYCLOBUTADIENE IN SYNTHESIS endo-TRICYCLO[4.4.0.02 5]DECA-3,8-DIEN-7,IO-DIONE... 

The synthesis of fUido-tricyclo[4.4.0.02 5]deca-3,8-dien-7,10-dione and verification of its endo-configuration has been reported earlier.3 This adduet is a useful starting material for the syntheses of tetracyclo-[5.3.0.02 6.03 10]deca-4,8-diene,s tricyclo[4.4.0.02 5]deca-3,7,9-triene,6 cis, syn, cjs-tricyclo[5.3.0.02,6]deca-4,8-dien-3,10-dione,7 and 4-oxahexa-cyclo[5.4.0.02 6.03 10.05 9.08,11]undecane.a... 

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. 

Key intermediate 368 of Swan s ( )-yohimbone (305) synthesis (169) has also been achieved by Kametani et al. (215). Thermolysis of 3,4-dihydro-l-(5-methoxybenzocyclobutanyl)-P-carboline hydrochloride (381) afforded deca-... 

S Kates, NA Sole, M Beyermann, G Barany, F Albericio. Optimized preparation of deca(L-alanyl)-L-valinamide by 9-fluorenylmethoxyloxycarbonyl (Fmoc) solid-phase synthesis on polyethylene glycol-polystyrene (PEG-PS) graft supports, with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) deprotection. Pept Res 9, 106, 1996. 

The cobalt(I)-catalysed 6 + 2-cycloadditions of cyclooctatetraene with monosubsti-tuted alkynes produced monosubstituted bicyclo[4.2.2]deca-2,4,7,8-tetraenes in good yields.185 The 6 + 3-cycloaddition of fulvenes (145) with 3-oxidopyrylium betaines (144) formed 5-8 fused oxa-bridged cyclooctanoids (146,147), which can be manipulated by cycloaddition reactions to produce key intermediates (148,149) for the synthesis of fused cyclooctanoid natural products e.g. lancifodilactones (Scheme 38).186,187... 

Pyrolysis of the sodium salt of the tosylhydrazone of 10-bicyclo[5.2.1 ]deca-none provides a remarkably easy synthesis of tricyclo [5.2.1.0 4>10] decane... 

The release of PBDEs to the environment can occur during initial synthesis, incorporation into products, and the use of such products. In China and mainly in the eastern part of the country, large quantities of deca-BDE have been produced. In 2001, the production of deca-BDE was 13,5001 per annum and the consumption has increased rapidly in recent years (Xia et al., 2005). In addition, three of the largest brominated FR manufacturers in the world (i.e., Great Lakes Chemical, Indianapolis, IN Albemarle Chemical, Richmond, VA and Dead Sea Chemical, Beer-Sheva, Israel) all have distributors in China. 

R. H. Martin, V. Libert, Helicenes. The Use of Resolved Hexahelicene-2-car-boxylic Acid as a Common Precursor for the Photochemical Synthesis of Optically Pure Octa-, Deca-, Undeca- and Trideca-helicenes. Thermal Racemiza-tion of Deca- and Undeca-helices, J. Chem. Res. (S) 1980, 130-131. 

Alkenylboron compounds couple with the representative organic halides or triflates (Scheme 28). Hexaalkylbenzene was synthesized by sixfold alkenylation (55) of hexabromobenzene followed by catalytic hydrogenation of the double bonds 11521. The reaction of 1-alkenylborane with 1-bromo-l-alkyne stereose-lectively provided ( )-enyne (56) which was then converted into ( ,Z)-hexa-deca-10,12-dienal, a sex pheromone of the melonworm 11531. Due to the difficulty of purification of a geometrical mixture, the stereoselective synthesis is critical for such dienes or trienes. The PGEi derivatives (57) were synthesized... 

Cyclobttlttdiene. Cyclobutadicne itself is unknown but the complex cyclobuta-dicnciron tricarbonyl (I, 2,140 3, 101) is readily available. The diene can be liberated from the complex as a transient intermediate for use in synthesis by oxidative degradation with ceric ammonium nitrate. If the reactants or products arc sensitive to the acidic solutions of CAN, lead tetraacetate in pyridine can be used as oxidant. Thus the reaction of cyclobutadienciron tricarbonyl with p-benzoquinone in the presence of CAN leads to formation of e [Pg.72]

Two laboratories - have reported the synthesis of isobullvaicne (7, tricyclo-[5.3.0.0 °]deca-3,5.,8-triene) in the same way from lithium cyclononatetraenide (6) by treatment with methylene chloride and n-butyllithium at a low temperature. The major product is isobullvalene (7), accompanied by the flOjannulene (8) and cij-9,10-... 

Unverzagt C, Seifert J. Chemoenzymatic synthesis of deca- and dodecasaccharide V-glycans of the bisecting type. Tetrahedron Lett. 2000 41 4549-4553. 

As implied above, the first synthesis of a sapphyrin was purely accidental and came about as the result of the reaction of the linear tetrapyrrolic precursor 5.1 with formic acid and HBr. Following oxidation with iodine, instead of obtaining the desired tetrapyrrolic corrole macrocycle, a different macrocycle was obtained (Scheme 5.1.1). This unexpected by-product was best formulated as being the deca-alkyl-substituted aromatic pentapyrrolic macrocycle 5.2. The unexpected formation... 

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