[CH:1]([C:3]1[CH:4]=[C:5]([C:13]([O:15][CH3:16])=[O:14])[C:6]2[C:11]([CH:12]=1)=[CH:10][CH:9]=[CH:8][CH:7]=2)=[CH2:2].C1C=CC(P(C2C=CC=CC=2)CCCCP(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.CC1(C)C(C)(C)OB[O:49]1.B(O[O-])=O.[Na+]>C1COCC1>[OH:49][CH2:2][CH2:1][C:3]1[CH:4]=[C:5]([C:13]([O:15][CH3:16])=[O:14])[C:6]2[C:11]([CH:12]=1)=[CH:10][CH:9]=[CH:8][CH:7]=2Methyl 3-ethenyl-1-naphthalenecarboxylate (1 eq.) from the previous step, [Ir(COD)Cl]2 (0.025 eq.) and DPPB (0.05 eq.) were combined in THF (0.12 M). To this solution was then added 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.2 eq.) and the resulting red solution was stirred at RT for 16 h. Finally, sodium perborate (0.1 M aqueous solution, 2 eq.) was added and the now black biphasic solution was vigorously stirred at RT for another 12 h. The aqueous layer was separated and back-extracted with ether. The combined organic extracts were then washed further with 1 N aq. NaOH, water and brine. This was then dried over Na2SO4, filtered and the filtrate concentrated in vacuo to afford a pale yellow oil. Purification of the crude product thus obtained by way of flash chromatography (SiO2, 9:1 (v/v) Hex:EtOAc→1:1 (v/v) EtOAc:Hex) afforded the title compound as a pale yellow oil.
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