Diastereoselective Synthesis of Actinobolin from D-Glucose by Application of a Novel [3 + 3] Annulation
作者:Dale E. Ward、Brian F. Kaller
DOI:10.1021/jo00094a040
日期:1994.7
The synthesis of 5,6-O-(2-propylidene)-N-desalanyl-N-[(4-methylphenyl)methanesulfonyl]actiobolin (37) is reported. The carbocyclic ring of 37 is constructed by a novel [3 + 3] annulation method involving sequential two-electron and one-electron allylation with the conjunctive reagent 5. The 4-amino-4,6-dideoxy-D-galactose derivative 25 is efficiently prepared from D-glucose and coupled with 5. The key step in the annulation is the diastereoselective 6-endo-trig radical cyclization of the unusual thiocarbamate 32. The stereoselectivity is postulated to result from the acetonide protecting group in 32. The conversion of 37 into actinobolin has been previously established.