Cyclohexene → 7-hydroxy-3-(4-methoxyphenyl)-2H-1-benzopyran

HRID 254886Notes

Reaction equation

HRID 254886 reaction equation
C([O:8][C:9]1[CH:26]=[CH:25][C:12]2[CH:13]=[C:14]([C:17]3[CH:22]=[CH:21][C:20]([O:23][CH3:24])=[CH:19][CH:18]=3)[CH2:15][O:16][C:11]=2[CH:10]=1)C1C=CC=CC=1.C1CCCCC=1>[OH-].[OH-].[Pd+2].C(O)C>[OH:8][C:9]1[CH:26]=[CH:25][C:12]2[CH:13]=[C:14]([C:17]3[CH:22]=[CH:21][C:20]([O:23][CH3:24])=[CH:19][CH:18]=3)[CH2:15][O:16][C:11]=2[CH:10]=1

Participants

5

Reactant 2

HCID 8079CyclohexeneHCID 595921047-benzyloxy-3-(4-methoxyphenyl)-2H-1-benzopyran

Product 1

HCID 98598477-hydroxy-3-(4-methoxyphenyl)-2H-1-benzopyran

Reagents, catalysts & solvents 2

HCID 9942167Palladium hydroxideCatalystHCID 702EthanolSolvent

Procedure

As shown in Scheme 2, 7-benzyloxy-3-(4-methoxyphenyl)-2H-1-benzopyran (compound 1) was reacted with n-Bu4NI/BCl3 and BCl3 to give haginin E (compound 2a) at a yield of 79% and 7-hydroxy-3-(4-methoxyphenyl)-2H-1-benzopyran (4′-O-methyl haginin E, compound 2b) at a yield of 81%, respectively. Treatment of compound 1 with Pd(OH)2/C (Pearlman's reagent) and cyclohexene in refluxing ethanol promoted O-debenzylation and reduction of the chromene ring in one step, giving 7-hydroxy-3-(4-methoxyphenyl)-1-benzopyran (compound 3a) at a yield of 94%. Compound 3a was subsequently demethylated by use of n-Bu4NI/BCl3 to give equol (compound 3b) at a yield of 95%.

Sources & evidence

ORD record
ord-0e00903d09f1423a98ba327161524376
Source dataset
uspto-grants-2011_01
Patent number
US07875735B2

Reaction notes

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