The preparation of racemic des-hydroxy stachybotrin C is described. Different approaches have been studied. Observations made in the course of the synthesis show the efficiency of the intermolecular cyclization between the diethyl acetal 19 and phenol 12 leading to the benzopyran moiety 17. Georg Thieme Verlag KG · Stuttgart · New York.
Tumma, Naresh,Jacolot, Maiwenn,Jean, Mickael,Chandrasekhar, Srivari,Van De Weghe, Pierre
supporting information
p. 2919 - 2922
(2013/02/22)
Synthetic studies on Sch 202596, an antagonist of the galanin receptor subtype GalR1: An efficient synthesis of (±)-geodin, the spirocoumaranone part of Sch 202596
An efficient and facile synthesis of (±)-geodin [(±)-2] corresponding to the spirocoumaranone part of Sch 202596 (1) was accomplished in a convergent manner. The synthetic method features (i) a coupling reaction of the aryl aldehyde 6 with the aryl lithium 7 generated in situ from the aryl bromide 8 to deliver the highly substituted diaryl methanol 24 (6+7→24) and ii) oxidative spirocyclization reaction of the benzophenone 4 to construct the requisite spirocoumaranone skeleton [4→(±)-2] as the key steps. The aromatic segments 6 and 8 were prepared from commercially available methyl 3,5-dihydroxybenzoate (9) and 5-methylresorcinol (10), respectively.