A synthesis of (-)-alantrypinone is described. The synthesis features the use of [Me3AlSPh]Li as a promoter of a 4-iminobenzoxazine to 4-quinazolinone rearrangement and as a reagent for the deprotection of an Fmoc-protected amino acid derivative. (C) 1999 Elsevier Science Ltd, All rights reserved.
A new route to the synthesis of an optically active illudane skeleton from (R)-(−)-pantolactone (4) is established. The tricyclic ring system was constructed by Michael–Michael-elimination reaction of the enolate of (3S,5R)-3-(tert-butyldimethylsilyloxy)-5-methoxymethyloxy-1-propionylcyclopentene (10) with ethyl cyclopropylidenacetate (3).