Chiral exo-Alkylidenecyclopentanes from (1S,4R)-7,7-Dimethyl-1-vinylbicyclo[2.2.1]heptan-2-one

(1S,4R)-7,7-Dimethyl-1-vinylbicyclo[2.2.1]heptan-2-one oxime in the system (CF₃CO)₂O-CF₃COOH and (1S,4R)-1-(1,2-dibromoethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-one in the system MeONa-MeOH undergo fragmentation to give exo-alkylidenecyclopentane derivatives, (4R)-4-cyanomethyl-5,5-dimethyl-1-[(1E)-trifluoroacetoxyethylidene]cyclopentane and isomeric (4R)-4-carboxymethyl-1-[(1ZE)-2-methoxyethylidene]-5,5-dimethylcyclopentanes, respectively. The trifluoroacetate derivative undergoes unusual rearrangement, yielding an equilibrium mixture of two isomers with endo- and exocyclic double bond.     

Synthetic approaches to homochiral bicyclo[5.2.1]decanes based on d-camphor

The Reformatsky reaction of bornanic enone (10-nor-1-vinylcamphor) with ethyl iodoacetate followed by iodocyclization afforded tricyclic iodolactone. Fragmentation of the latter initiated by HgO—I₂ gave rise to bicyclic iodoxolactone. Attempts to perform cyclization of this iodoxolactone analogously to intramolecular alkylation of CH-acids with halogen-containing electrophiles failed.     

Some Transformations of (-)-(1S,4R)-1-Vinyl-7,7-dimethyl-bicyclo[2.2.1]heptan-2-one

Reactions were studied of (-)-(1S,4R)-1-vinyl-7,7-dimethylbicyclo[2.2.1]heptan-2-one with ethyl acetate lithium derivative, potassium acetylide, ozone, with a system OsO₄-N-methylmorpholine N-oxide, and some subsequent transformations of the products obtained.     

Oxidative dimerization of vinylbornylacetylenes under the action of mercuric acetate

Vinylbornylacetylenes and their trimethylsilyl derivatives undergo oxidative dimerization in the presence of an Hg(OAc)₂—HgO system in MeOH to give the corresponding diacetylenes.     

Vicinal Dibromo and Hydroxy(methoxy) Bromo Derivatives of (1R,4R)-7,7-Dimethyl-1-vinylnorbornan-2-one. Regio- and Stereoselectivity Aspects

Reactions of (1R,4R)-7,7-dimethyl-1-vinylnorbornan-2-one with bromine in carbon tetrachloride and with N-bromosuccinimide in methanol gave the corresponding C^{1 '}-epimeric dibromo and methoxy bromo derivatives. Their structure was determined on the basis of spectral data.     

New 2,10-Functionalized Camphor Derivatives

Synthetic routes to precursors of tricyclic camphor derivatives fused at the 2,10-positions, the corresponding halohydrins and dimethyl acetal, are discussed.     

New Camphor Derivatives Functionalized at C3 and C10

Base-catalyzed condensation of 10-methylenecamphor with diethyl oxalate gave the corresponding (Z)-3-ethoxycarbonyl(hydroxy)methylene derivative which was converted into methyl ether and acetate. The Z-methyl ether undergoes isomerization into the E-methyl ether on treatment with N-bromosuccinimide in the presence of radical initiator [azobis(isobutyrodinitrile)]. (Z)-3-Ethoxycarbonyl(hydroxy)methylene-10-methylenecamphor smoothly reacts with N-bromosuccinimide to afford stereoisomeric 3-bromo derivatives.