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Carbocations

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Full-Text Articles in Chemistry

Dehydrotropylium-Co2(Co)6 Ion. Generation, Reactivity And Evaluation Of Cation Stability, Sheida Amiralaei, James Gauld, James R. Green Apr 2011

Dehydrotropylium-Co2(Co)6 Ion. Generation, Reactivity And Evaluation Of Cation Stability, Sheida Amiralaei, James Gauld, James R. Green

Chemistry and Biochemistry Publications

The dehydrotropylium–Co2(CO)6 ion was generated by the action of HBF4 or BF3OEt2 on the corresponding cycloheptadienynol complex, which in turn has been prepared in four steps from a known diacetoxycycloheptenyne complex. The reaction of the cycloheptadienynol complex via the dehydrotropylium–Co2(CO)6 ion with several nucleophiles results in substitution reactions with reactive nucleophiles (N>1) under normal conditions, and a radical dimerisation reaction in the presence of less reactive nucleophiles. Competitive reactions of the cycloheptadienynol complex with an acyclic trienynol complex show no preference for generation of the dehydrotropylium–Co2 …


Vinylogous Nicholas Reactions In The Synthesis Of Icetexane, Faveline, And Related Ring Systems, Izabela Kolodziej, James R. Green Jan 2011

Vinylogous Nicholas Reactions In The Synthesis Of Icetexane, Faveline, And Related Ring Systems, Izabela Kolodziej, James R. Green

Chemistry and Biochemistry Publications

The intramolecular vinylogous Nicholas reactions of aryl substituted acetoxy enyne-Co(2)(CO)(6) complexes afford tricyclic 6,7,6-ring systems and related systems in good yield.


Cyclohepta[De]Naphthalenes And The Rearranged Abietane Framework Of Microstegiol Via Nicholas Reaction Chemistry, Rafiq A. Taj, Anusha Abhayawardhana, James R. Green Jan 2009

Cyclohepta[De]Naphthalenes And The Rearranged Abietane Framework Of Microstegiol Via Nicholas Reaction Chemistry, Rafiq A. Taj, Anusha Abhayawardhana, James R. Green

Chemistry and Biochemistry Publications

Nicholas reactions on 2,7-dioxygenated naphthalenes give C-1 monosubstitution and C-1/C-8 disubstitution in most cases. From gamma-carbonyl cation monocondensation product 3b or alkyne-unsubstituted dicondensation product 4a, cyclohepta[de]naphthalenes bearing no substituents, gem-dimethyl substituents, and a ketone function, and the rearranged abietane framework of microstegiol may be prepared.