Reaction of carbenes with bicyclo[2.1.0]pentane

Bicyclo[2.1.0]pentane reacts with phenylcarbene and dicarbomethoxycarbene by simple insertion at the cyclobutane methylene position. By contrast, difluorocarbene reacts by two bond cleavage to give 1,1-difluoro-1,5-hexadiene.     

Microwave spectra and dipole moments of bicyclo [2.2.1]-hepta-7-one and bicyclo [2.2.1]hept-2-en-7-one

The microwave spectra of bicycle [2.2.1] hepta-7-one (I), bicyelo [2.2.1] hept-2-en-7-one (II), and exo-5,6-bisdeuteriobicyclo [2.2.1] hept-2-en-7-one (III) have been recorded in the region between 26.5 and 40.0 GHz. The rotational constants in the order A, B, C for the title compounds are 2773.24±0.31, 2301.74±0.04, and 2133.96±0.02 (I); 2979.22±0.08, 2418.60±0.01, and 2235.51±0.01 (II); and 2789.67±0.06, 2385.24±0.01, and 2150.60±0.01 (III). The rotational constants of four vibrationally excited states were also determined for (II). Quadratic Stark effect measurements on the 7₁₆ ← 6₁₅ transition of (I) gave ¦μ_a¦=2.99±0.03. Similar measurements on two 5 ← 4 and 4 ← 3 transitions of (II) gave ¦μ_a¦=2.88±0.03, ¦μ_b¦=0.39±0.03, ¦μ_c¦=0, and ¦μ_total¦=2.91±0.04.     

Reaction of bicyclo [1.1.0] butane with mercury acetate

Russian Chemical Bulletin -     

Asymmetric synthesis of bicyclo[4.3.1]decadienes and bicyclo[3.3.2]decadienes via [6 + 3] trimethylenemethane cycloaddition with tropones

The cyanosubstituted trimethylenemethane donor undergoes palladium-catalyzed [6 + 3] cycloaddition with a variety of tropones to yield bicyclo[4.3.1]decadienes in excellent regio-, diastereo-, and enantioselectivity. Products of the Pd-TMM [6 + 3] cycloaddition participate in a thermal [3,3] sigmatropic rearrangement to yield bicyclo[3.3.2]decadienes in good yield.     

The synthesis of bicyclo[6.2.0]decapentaene

The parent bicyclo[6.2.0]decapentaene is synthesized for the first time by thermal ring opening of its valence isomer. Thermal dimerization of the compound is also described.     

Acid-catalyzed synthesis of bicyclo[3.n.1]alkenediones

An acid-catalyzed Dieckmann-type reaction has been developed to access functionalized bicyclo[3.2.1]alkenediones. This methodology has been successfully extended to more substituted and larger ring homologues, providing a new and efficient route to the core of numerous attractive natural products and their analogues.     

One-pot palladium-catalyzed synthesis of 2,3-disubstituted bicyclo[2.2.1]heptanes and bicyclo[2.2.1]hept-5-enes

A new and highly stereoselective palladium-catalyzed synthesis is reported, based on two subsequent insertions of the bicyclo[2.2.1]heptene system into an aryl or vinylpalladium bond, formed in situ from aryl or vinyl bromides.     

Regioselective copper-mediated synthesis of thieno[2,3-c]pyrane-7-one, indolo[2,3-c]pyrane-1-one, and indolo[3,2-c]pyrane-1-one

In the presence of copper(I) iodide, heteroaromatic β-iodo-α,β-unsaturated carboxylic acid systems opposed to terminal alkyne afford selectively 6-endo-dig cyclization products via a tandem coupling oxacyclization reaction.     

Novel dimerisation of bicyclo[3.3.0]oct-2-en-3-one

Application of the intramolecular Wadsworth-Emmons reaction to bicyclo[3..3.0]oct-2-en-3-ones results in the formation of a novel dimer (11) of the parent member (6) whose structure has been determined by X-ray crystallography.     

New synthesis of bicyclo[1.1.0]butane hydrocarbons

Conclusions A new general synthesis is proposed for bicyclo[1.1.0]butanes, by 1,3-cyclization of 1-bromo-chloromethylcyclopropanes, and a two-step synthesis of the latter from available allyl chlorides has been developed.Deceased.Translated from Izvestlya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2043–2047, September, 1985.     

Acylation of bicyclo[3.1.0]hexane and bicyclo[5.1.0]octane with pivaloyl tetrafluoborate

Conclusions When bicyclo[3.1.0]hexane and bicyclo[5.1.0]octane are acylated with pivaloyl tetrafluoborate the three-membered ring is opened to respectively give 2-methylpivaloylcyclopentane and 2-methylpivaloylcycloheptane derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2614–2616, November, 1975.     

Synthesis of the cyclohexane core of phomactins and a new route to the bicyclo[9.3.1]pentadecane diterpenoid skeleton

Conjugate reduction of an enone accompanied by in situ intramolecular aldol condensation was used to construct the tetrasubstituted cyclohexane nucleus of phomactins. Subsequent relay ring-closing metathesis completed the nine-membered ansa bridge of the diterpenoid framework.     

Reaction of benzo[α]Phenoxazin-9-one with ethylenimine

The reaction of benzo[a]phenoxazin-9-one and its 5-sulfides with ethylenimine has given 11-ethyleneamino derivatives. It has been shown that in contrast to the arylamines, which enter position 5 of benzo[a]-phenoxazin-9-one, ethylenimine reacts at the quinoid nucleus of the phenoxazine system. Absorption spectra in the visible region for phenoxazinones substituted in the quinoid nucleus have been recorded.