富勒烯[60]的光化学反应研究

从光物理出发,综述了近几年富勒烯「６０」的光化学反应研究进展。Ｃ６０能发生诸多的光化学反应：（１）光氧化;（２）光氢化还原;（３）「２＋２」光环化加成;（４）与叔胺的光加成;（５）与氨基酸的光加成;（６）与金属有机化合物的光加成。     

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.     

Sila-3 et germa-3 bicyclo[3.1.0] hexanes

The 3-sila- and 3-germabicyclo[3.1.0] hexanes, with various substituents at the heteroatom, are prepared from the corresponding 1-sila- and 1-germacyclo-3-pentenes in two different ways. The method of synthesis and the chemical reactivity of this new class of heterobicyclic products are determined by the heteroatom and the alkyl or aryl substituent bonded to silicon or germanium.     

Catalytic isomerization of 1,5-enynes to bicyclo[3.1.0]hexenes

The cycloisomerization of 1,5-enynes catalyzed by cationic triphenylphosphinegold(I) complexes produces bicyclo[3.1.0]hexenes. Substitution at all positions of the 1,5-enyne is tolerated, leading to a wide range of bicyclo[3.1.0]hexane structures, including those containing quaternary carbons. Substrates containing a 1,2-disubstituted olefin undergo stereospecific cycloisomerization (cis-olefin produces cis-cyclopropane, and trans-olefin gives trans-cyclopropane). Additionally, enantioenriched bicyclo[3.1.0]hexenes can be obtained from the gold(I)-catalyzed cycloisomerization of enantioenriched 1,5-enynes with excellent chirality transfer. The preparation of tricyclic systems is accomplished through a gold(I)-catalyzed tandem cycloisomerization-ring enlargement reaction.     

二环[3.1.0]己烷酮衍生物的固相不对称光化学反应研究

由二环庚二烯为起始原料合成二环己烷酮类衍生物,以手性胺作为手性辅助剂进行固相不对称光化学反应研究,探讨了反应时间和反应温度对光化学裂解产率和对映选择性的影响,ee值最高达到75%。     

Photochemistry of 3-substituted bicyclo[3.1.0]hex-3-en-2-ones. Regioselective synthesis of ortho-substituted phenols by Pauson-Khand reaction

[reaction: see text] 3-Substituted bicyclo[3.1.0]hex-3-en-2-ones 3, easily obtained by Pauson-Khand reaction between terminal alkynes and cyclopropene, have been quantitatively converted into ortho-substituted phenols 4 by irradiation with UV light (350 nm). The kinetics and mechanism of this photochemical process have been studied by means of FT-IR and semiempirical (AM1 3x3 CI) calculations.     

Dynamics of the degenerate rearrangement of bicyclo[3.1.0]hex-2-ene

Quasiclassical direct dynamics simulations are applied to a 4-fold degenerate rearrangement which yields a nonstatistical product distribution. The simulated product ratio agrees with experiment and is found to be entirely dynamically determined. Trajectory lifetimes are on the order of a low-frequency vibrational period. The interaction of reaction momentum with the geometric features of the potential surface produces selectivity despite a common energy barrier. A geometric model is described for qualitatively estimating much of the dynamically determined product ratio independently of trajectory calculations. The characteristics of this reaction are expected also to apply to others involving modestly stabilized diradical intermediates.     

Generation and reactivity of sterically hindered bicyclo[3.1.0]hex-1-enes

2-t-butylbicyclo[3.1.0]hex-1-ene dimerizes primarily by a [σ+ π] way, whereas 2,5-di-t-butylbicyclo[3.1.0]hex-1-ene undergoes an unusual hydrogen shift reaction to 1,3-di-t-butyl-2-methylcyclopentadiene.     

Enantioselective syntheses of bicyclo[3.1.0]hexane carboxylic acid derivatives by intramolecular cyclopropanation

Enantioselective syntheses of bicyclo[3.1.0]hexane carboxylic acid derivatives are described. The syntheses were achieved by an intramolecular cyclopropanation as the key step, starting from enantiomerically pure starting materials that are commercially available.     

Photochemistry of 3,7-Bis(arylmethylene)bicyclo[3.3.1]nonane Derivatives

UV irradiation of trans-trans-3,7-bis(arylmethylene)bicyclo[3.3.1]nonane-2,6-diones leads to their complete or partial transformation into the corresponding cis-cis isomers. Irradiation of trans-trans-3,7-bis(arylmethylene)bicyclo[3.3.1]nonane-2,6-diol in ether in the presence of CuCl results in intramolecular cyclization involving the exocyclic double bonds and one benzene ring to give exo-7endo-10-dihydroxy-2-phenyl-3,4-benzotetracyclo[4.3.3.18,11.01,6]tridecane.     

Bicyclo[3.1.0]hex-(1,5)-ene and bicyclo[4.1.0]hept-(1,6)-ene

The formation and trapping of bicyclo[3.1.0]hex-(1,5)-ene and bicyclo[4.1.0]hept-(1,6)-ene from the corresponding vicinal dibromides is described.     

Synthesis and Photochemistry of Novel 3,5-Diacetyl-1,4-dihydropyridines. II [1]

Summary. In continuation of previous work some novel 3,5-diacetyl-1,4-dihydropyridine derivatives were synthesized and their photochemical behavior was studied under oxygen and argon atmosphere. Oxidation of the dihydropyridine ring and formation of pyridine derivatives was the result of the reaction. The presence of oxygen affects not only on the rate of oxidation, but also the formation of some unidentified by-products was observed on irradiation under this atmosphere.     

Potential surface for the quadruply degenerate rearrangement of bicyclo[3.1.0]hex-2-ene

Previous experimental studies have shown that bicyclo[3.1.0]hex-2-ene and substituted derivatives undergo thermal rearrangements to form three products identical to the starting material save for the position of the labeling substituents. Despite the likely involvement of a symmetric diradical intermediate, cyclohexene-3,5-diyl, these products are formed at unequal rates. DFT (B3LYP), CASSCF, and CASPT2 calculations were performed to map out the details of the potential energy landscape for the reaction. A qualitative hypothesis, based on dynamical considerations, is offered to explain the observed nonstatistical product distribution.     

Synthesis and rearrangement of [1,1′-bicyclobutyl]-1-ols and spiro[3.4]octan-5-ols: a general access to bicyclo[3.3.0]octenes (hexahydropentalenes)

Several new Grignard reagents based on substituted cyclobutanes have been generated and added to cyclobutanones to yield mono- to trimethylated [1,1′-bicyclobutyl]-1-ols. Mono- to trimethylated spiro[3.4]octan-5-ols have been prepared from the parent ketone via alkylation and/or addition reactions. Upon treatment with acid, all [1,1′-bicyclobutyl]-1-ols and spiro[3.4]octan-5-ols rearrange to yield a single bicyclo[3.3.0]octene.     

A remarkably simple chemicoenzymatic approach to structurally complex bicyclo[3.1.0]hexane carbocyclic nucleosides

[reaction: see text] Intramolecular cyclopropanation of a carbene engendered from the corresponding diazo beta-ketoester produced the desired bicyclo[3.1. 0]hexane pseudosugar. Purine nucleosides obtained via Mitsunobu coupling were resolved with adenosine deaminase. The requisite beta-ketoester was assembled in one step from ethyl acetoacetate and acrolein.