Stereoselective synthesis of 2,4,5-trisubstituted tetrahydropyrans using an intramolecular allylation strategy.
A highly stereoselective route to 2,4,5-trisubstituted tetrahydropyrans is reported. The key step employs an intramolecular allylation of a (Z)-allylsilane onto an aldehyde under Brønsted acid activation. Complete 1,4-stereoinduction accounts for the formation of only two out of the possible four THP products. The level of 1,3-stereoinduction is optimal when the reaction is carried out in an apolar solvent, which is in accord with electrostatics being key to controlling this aspect of the stereoselectivity.
Jervis
Peter J
PJ
School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Kariuki
Benson M
BM
Cox
Liam R
LR
D011714:Pyrans / Q000138:chemical synthesis*; D013237:Stereoisomerism
D011714:Pyrans