Cyclohept-3-en-l-one

When we extended the activated olefins to cyclohept-2-en-l-one and cyclooct-2-en-l-one we found that the reaction is very complicated, because the Lewis bases, solvents and the ring-size of the cyclic enone can all significantly affect the MBH reaction rate and even the reaction product. The reaction of cyclohept-2-en-l-one with A-arylidene-4-methylbenzenesulfonamides afforded the usual MBH adducts 203 along with abnormal adducts 204, whereas the corresponding reaction of cyclooct-2-en-l-one provided different aldol products (205-207) depending upon the Lewis base employed (no MBH adduct was formed in any of the cases) (Scheme 2.104). Moreover, the formation of aldol products 209 along with the usual MBH adducts 208 has been observed in the reaction between cyclopent-2-en-l-one and aromatic aldehydes in the presence of BU3P (Scheme 2.105). 

Irradiation of 3-(alk-l-ynyl)cyclohept-2-en-l-ones (32) leads to selective formation of tricyclic head-to-head dimers. However, in the presence of 2,3-dimethylbuta-1,3-diene, [2 + 2], [4 + 2] or [4 + 4] cycloadducts can be obtained, depending on the enone structure. In the case of cyclohex-2-enones, photocycloaddition to the diene leads to cyclobutane adducts. A special case are 3-(alk-l-ynyl)-cyclohex-2-enones, which undergo [2 + 2] cycloaddition exclusively at the C=C bond to afford 3-cyclobutenylcyclo-hex-2-enones (33). ... 

Cyclohepta[4,5)pyrrolo[l,2-fl]imidazoles, 2-aryl-, halogenation. 59, 283 Cyclohepta[4,5)pyrrolo[3,2-e][l,2,4]triazine, 3-chloro- 10-(4-chlorobutyD-5,6,7,8,9,10-hexahydro-, 59, 50 3//-Cyclohept(e]isoxazoles, 3a,4,5,6,7,8-hexahydro-, 60, 311-3 Cyclohex-2-en-l-ones, 2- and 3-bromo-, regioselectivity of nitrile oxide cycloaddition, 60, 304 Cyclols, piperazine-2,5-dione-related, 57, 211-7... 

Xanthatin (3-methylene-7-methyl-6-[3-oxo-l-buten-l-yl]cyclohept-5-ene-[10,ll- ]furan-2-one, (-)-2-[(7/ )-7t-hydroxy-5c-methyl-4-(3-oxobut-l-en- -yl)cyclohept-3-en-r-yl)-acrylic acid lactone [26791-73-1] M 246,3, m 114.5-115 , [a] -20 (c 2, CHCI3), Crystalhse... 

Cyclohept-2-enone and cyclo-oct-2-enone undergo ring-contraction to 1-acetyl-cyclopentene and 1-acetylcyclohexene, respectively, in aqueous ethanol containing triethylamine at 140 Treatment of eucarvone with sodium hydride and methyl iodide gave a mixture of products including the bicyclic compounds 3-methylcar-4-en-2-one and l,3-dimethylcar-4-en-2-one. Attempts to dehydrate cycloheptene (237) gave mixtures of dimethylisopropylbenzenes. ... 

Irradiation of benzyl cyclohept-l-enyl ketone through pyrex in the presence of BF3-etherate gave (311) via a singlet state process. y,5-Epoxyeucarvone (312) gave the rearranged products 8-oxo-l,4,4,-trimethylbicyclo[3,2,l]oct-6-en-2-one (46%) and... 

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