333347-40-3Relevant academic research and scientific papers
Synthesis of hepialone and related dihydro-γ-pyrones by various (3+3) methods
Dree?en, Sylvia,Schabbert, Silke,Schaumann, Ernst
, p. 245 - 251 (2007/10/03)
Four routes towards the synthesis of the natural dihydropyrans 1, i.e. from chiral oxiranes 9 as C2O building blocks and sulfur-substituted allyl (14) or propargyl (10, 11) anions as C3 fragments, have been investigated. The resulting C5O derivatives 4, 8 could be cyclized after generation of a carbonyl group by oxidation (6, 7) or hydrolysis (8). Here, the Pummerer reaction of 6 turned out to be only moderately efficient, whereas the hydroxylation of sulfone 7b allowed smooth access to dihydropyran 1b. Cyclization of bis(homoallyl) alcohol 13 was achieved by acid catalysis, but attempts to introduce a methyl group at C-2 of dihydropyran 12 did not meet with success.
