p-Toluenesulfonic acid → (2R,2'S,3'R,4'S,5'R,6'R)-3',4',5'-tris(benzyloxy)-6'-(benzyloxymethyl)-6-chloro-5-(4-ethylbenzyl)-2-methoxy-3',4',5',6'-tetrahydro-2H-spiro[benzofuran-3,2'-pyran]

HRID 1713612Notes

Reaction equation

[CH2:1]([O:8][C@@H:9]1[C@@H:14]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C@H:13]([O:23][CH2:24][C:25]2[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=2)[C@@H:12]([CH2:31][O:32][CH2:33][C:34]2[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=2)[O:11][C@:10]21[C:43]1[CH:44]=[C:45]([CH2:49][C:50]3[CH:55]=[CH:54][C:53]([CH2:56][CH3:57])=[CH:52][CH:51]=3)[C:46]([Cl:48])=[CH:47][C:42]=1[O:41][C@H:40]2[OH:58])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[C:59]1(C)C=CC(S(O)(=O)=O)=CC=1.CCOC(C)=O>CO.COC(OC)OC>[CH2:1]([O:8][C@@H:9]1[C@@H:14]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C@H:13]([O:23][CH2:24][C:25]2[CH:26]=[CH:27][CH:28]=[CH:29][CH:30]=2)[C@@H:12]([CH2:31][O:32][CH2:33][C:34]2[CH:39]=[CH:38][CH:37]=[CH:36][CH:35]=2)[O:11][C@:10]21[C:43]1[CH:44]=[C:45]([CH2:49][C:50]3[CH:55]=[CH:54][C:53]([CH2:56][CH3:57])=[CH:52][CH:51]=3)[C:46]([Cl:48])=[CH:47][C:42]=1[O:41][C@H:40]2[O:58][CH3:59])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

Conditions

Temperature: 70 °C

Procedure

To a solution of 27 (35 mg, 44 μmol) in anhydrous MeOH (1 mL) and trimethylorthoformate (0.5 mL) was added 4-toluenesulfonic acid (15 mg). The mixture was heated in a closed vial at 70° C. overnight, cooled to ambient temperature, loaded onto a preparatory TLC plate, and developed using 15% EtOAc in petroleum ether to give 54 (25 mg, 70% yield). LC/MS m/z 834 (M+Na).

Workup

temperaturecooled to ambient temperature

Sources & evidence

ORD record: ord-8b10dbd4e0984b84a39339edc61468af
Source dataset: uspto-grants-2010_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07795228B2

Reaction notes

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