236387-87-4Relevant articles and documents
Diastereoselective 6-exo radical cyclizations of oxime ethers: Total synthesis of 7-deoxypancratistatin
Keck, Gary E.,McHardy, Stanton F.,Murry, Jerry A.
, p. 4465 - 4476 (1999)
The development of an approach leading to the total synthesis of 7- deoxypancratistatin is described. The key features of the approach include a 6-exo radical cyclization reaction between a benzylic radical and an O- benzyloxime ether to establish the C(4a)-C(10b) bond. The stereochemistry of this reaction was examined in both acyclic radical precursors and ones in which the aryl moiety was tethered to the C1 oxygen substituent. It was found that the use of such a tether was essential to obtain the stereochemical result required for the synthesis. The correct absolute and relative configurations at the hydroxylated carbons C1-C4 were obtained using D-gulonolactone as the source of C(10b)-C(4a).