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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Nicholas Reactions In The Construction Of Cyclohepta[De]Naphthalenes And Cyclohepta[De]Naphthalenones. The Total Synthesis Of Microstegiol, Rafiq Taj, James R. Green
Nicholas Reactions In The Construction Of Cyclohepta[De]Naphthalenes And Cyclohepta[De]Naphthalenones. The Total Synthesis Of Microstegiol, Rafiq Taj, James R. Green
Chemistry and Biochemistry Publications
The application of the Nicholas reaction chemistry of 2,7-dioxygenated naphthalenes in the synthesis of cyclohepta[de]napthalenes and in the synthesis of (±)-microstegiol (1) is presented. The substitution profile of Nicholas monosubstitution (predominantly C-1) and disubstitution reactions (predominantly 1,6-) on 2,7-dioxygenated napthalenes is reported. Application of a 1,8-dicondensation product and selected C-1 monocondensation products to the construction of cyclohepta[de]naphthalenes by way of ring closing metathesis and intramolecular Friedel−Crafts reactions, respectively, is described. Deprotection of the C-7 oxygen function to the corresponding naphthol allows tautomerization to cyclohepta[de]naphthalene-1-ones upon seven-membered-ring closure in most cases, and replacement …
Intramolecular Nicholas Reactions In The Synthesis Of Dibenzocycloheptanes. Synthesis Of Allocolchicine Nsc 51046 And Analogues And The Formal Synthesis Of (−)-Allocolchicine, Sinisa Djurdjevic, Fei Yang, James R. Green
Intramolecular Nicholas Reactions In The Synthesis Of Dibenzocycloheptanes. Synthesis Of Allocolchicine Nsc 51046 And Analogues And The Formal Synthesis Of (−)-Allocolchicine, Sinisa Djurdjevic, Fei Yang, James R. Green
Chemistry and Biochemistry Publications
The preparation of dibenzocycloheptyne-Co2(CO)6 complexes by intramolecular Nicholas reactions of biaryl-2-propargyl alcohol-Co2(CO)6 derivatives is described. Reductive decomplexation of the dibenzocycloheptyne-Co2(CO)6 complexes affords the corresponding dibenzocycloheptenes, individual members of which have been employed in a formal total synthesis of (−)-allocolchicine, the preparation of 6,7-dihydro-3,4,9,10,11-pentamethoxy-5H-dibenzo[a,c]cyclohepten-5-one, and the enantioselective total syntheses of NSC 51046 and its 3,8,9,10-tetramethoxy regioisomer.