Syntheses with sulfones XLVI : stereoselective preparation of 2- benzenesulfonyl-1,3-dienes and 2-benzenesulfonyl-1,4-dienes

Unravelling the Synthesis and Chemistry of Stable, Acyclic, and Double‐Deficient 1,3‐Butadienes: An endo‐Selective Diels–Alder Route to Hedgehog Pathway Inhibitors

“…McIntosh, Bäckvall and Spino's groups synthesized and explored the dienes 4 (Figure ) bearing only one electron‐withdrawing group in the Diels–Alder cycloaddition reactions . However, these dienes were prone to nucleophilic additions and undesired dimeric cycloadditions . In particular, dienes with an ester moiety had to be generated in situ for any further transformation .…”

Carotenoids and polyterpenoids

“…(25), alloxanthin (7,8,7',8'-tetradehydro-/?,/?-carotene-3,3'-diol) (65), capsorubin (3,3'-dihydroxy-~,~-carotene-6,6'-dione) (66), and astaxanthin (34) were stable in methanolic solution, whereas the sulphates of carotenoids that contain vicinal diol, phenolic, or tertiary hydroxyl groups, e.g. caloxanthin (p,/?carotene-2,3,3'-triol (67), nostoxanthin (p,/?-carotene-2,3,2',3'tetraol) (68), 3-hydroxyisorenieratene (+,#-caroten-3-01) (69), (72), and hydroxychlorobactene (1 ',2'dihydro-@,$-caroten-1'-01) (73) were less stable.…”

Asymmetric Vinylogous Aldol-type Reactions of Aldehydes with Allyl Phosphonate and Sulfone

“…Furthermore, the addition of allyl sulfone to benzaldehyde catalyzed by a phosphine-based strong base was studied by Verkade and co-workers, which delivered the α-adduct in 63% yield at −78°C (Scheme 1B) (Kisanga and Verkade, 2002). The same reaction promoted by stoichiometric n BuLi also afforded the α-adduct exclusively, which was employed to prepare acyclic 2-phenylsulfonyl 1,3-diene in 89% yield (Cuvigny et al., 1983, Cuvigny et al., 1986, Chinkov et al., 2003). Obviously, it is challenging to overcome the inherent α-selectivity in the aldol-type reactions of allyl phosphonate and allyl sulfone.…”