Stereocontrol in organic synthesis using silicon-containing compounds. A synthesis of (±)-dihydronepetalactone using the SE2′ reaction of an allylsilane
A propargylic alcohol 24 with the propynyl group exo on the norbornene framework was used in a stereospecific synthesis of the mixture of allylsilanes 27 and 28. The stereospecific reaction of this mixture with peracid gave, with a high level of stereocontrol, the norbornenol 25 having the alkenyl group endo on the norbornene framework. This substrate underwent an oxyanion accelerated Cope rearrangement setting up all four stereocentres in a synthesis of (±)-dihydronepetalactone 6.