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Synthesis of Hepialone and Related Dihydro‐γ‐pyrones by Various (3+3) Methods
Author(s) -
Dreeßen Sylvia,
Schabbert Silke,
Schaumann Ernst
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200101)2001:2<245::aid-ejoc245>3.0.co;2-z
Subject(s) - chemistry , dihydropyran , propargyl , hydroxylation , sulfone , pummerer rearrangement , chemoselectivity , hydrolysis , organic chemistry , alcohol , sulfur , catalysis , propargyl alcohol , allyl alcohol , enantioselective synthesis , medicinal chemistry , acetic anhydride , enzyme
Four routes towards the synthesis of the natural dihydropyrans 1 , i.e. from chiral oxiranes 9 as C 2 O building blocks and sulfur‐substituted allyl ( 14 ) or propargyl ( 10 , 11 ) anions as C 3 fragments, have been investigated. The resulting C 5 O 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.