Intramolecular Nicholas Reactions in the Synthesis of Dibenzocycloheptanes. Synthesis of Allocolchicine NSC 51046 and Analogues and the Formal Synthesis of (−)-Allocolchicine
作者:Sinisa Djurdjevic、Fei Yang、James R. Green
DOI:10.1021/jo101953n
日期:2010.12.3
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