%0 Journal Article %J European Journal of Organic Chemistry %D 2011 %T Construction of the 5,10b-phenanthridine skeleton using [3+2]-cycloaddition of a non-stabilized azomethine ylide: total synthesis of (+/-)-maritidine and (+/-)-crinine alkaloids %A Pandey, Ganesh %A Gupta, Nishant R. %A Gadre, Smita R. %K alkaloids %K Azomethine ylides %K Cycloaddition %K Natural products %K Ylides %X

Vicinal quaternary and tertiary stereocenters of the 5,10b-phenanthridine skeleton 1 are constructed simultaneously in one step by the [3+2]-cycloaddition of non-stabilized azomethine ylide 9, generated by sequential double desilylation of 10 utilizing silver(I) fluoride as a one-electron oxidant. The regioas well as stereochemical origin of this cycloaddition reaction is explained through a favorable transition state 9''. The strategy is successfully applied for the total synthesis of the biologically active alkaloids (+/-)-maritidine (1a), (+/-)-crinine (1b), and their analogues (1d, 1e, and 1f).

%B European Journal of Organic Chemistry %I WILEY-V C H VERLAG GMBH %C PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY %P 740-750 %8 FEB %G eng %N 4 %3 Foreign %4 3.07 %R 10.1002/ejoc.201001263