- A diastereoselective route to trans-2-aryl-2,3-dihydrobenzofurans through sequential cross-metathesis/isomerization/allylboration reactions: Synthesis of bioactive neolignans
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A new highly diastereoselective synthetic route to trans-2,3-dihydrobenzofuran systems, in particular those bearing an aryl substituent at the C2 position, is described. The cornerstone of our strategy is the implementation of a cross-metathesis/isomerization/allylboration sequence starting from 2-allyl-substituted phenols and aldehydes. After an intramolecular Mitsunobu cyclization step, the anti-homoallylic alcohols allow the synthesis of the desired skeleton in a stereoselective fashion. As an illustration, we used this strategy for the preparation of the dihydrodehydrodiconiferyl alcohol (1a), a natural dihydrobenzofuran neolignan, as well as for a formal synthesis of its O-demethylated derivative 1b. An enantioselective version of this approach employing a chiral phosphoric acid in the allylboration step is also studied.
- Hemelaere, Rémy,Carreaux, Fran?ois,Carboni, Bertrand
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supporting information
p. 2470 - 2481
(2015/04/22)
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- Benzo[f][1,2]oxasilepines in the synthesis of dihydro[b]benzofuran neolignans
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A short synthesis of neolignans with a dihydrobenzo[b]furan skeleton is described. The strategy is based on a ring-closing metathesis to produce benzo[f][1,2]oxasilepines which are condensed with aromatic aldehydes in a modified Sakurai-Hosomi reaction. Natural dihydrodehydrodiconiferyl alcohol (1) and 3-O-demethyldihydrodehydrodiconiferyl alcohol (2) have been prepared in this way. Georg Thieme Verlag Stuttgart.
- García-Mu?oz, Sergio,Jiménez-González, Leticia,álvarez-Corral, Míriam,Mu?oz-Dorado, Manuel,Rodríguez-García, Ignacio
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p. 3011 - 3013
(2007/10/03)
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