Trifluoroacetic acid → 2'-Oxo-1,2'-dihydrospiro[1-benzofuran-3,3'-indole]-6-carbonitrile
Reaction equation
C1(C(C2C=CC=CC=2)[N:8]2[C:16]3[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=3)[C:10]3([C:20]4[CH:21]=[CH:22][C:23]([C:25]#[N:26])=[CH:24][C:19]=4[O:18][CH2:17]3)[C:9]2=[O:27])C=CC=CC=1.FC(F)(F)C(O)=O>C([SiH](CC)CC)C>[O:27]=[C:9]1[C:10]2([C:20]3[CH:21]=[CH:22][C:23]([C:25]#[N:26])=[CH:24][C:19]=3[O:18][CH2:17]2)[C:11]2[C:16](=[CH:15][CH:14]=[CH:13][CH:12]=2)[NH:8]1Participants
4
Procedure
To a suspension of 1′-(diphenylmethyl)-2′-oxo-1′,2′-dihydrospiro[1-benzofuran-3,3′-indole]-6-carbonitrile (1.9 g, 4.4 mmol) in triethylsilane (5.0 mL) was added trifluoroacetic acid (10.0 mL). The solution was heated at reflux for 6 h, allowed to cool to ambient temperature and concentrated in vacuo to obtain 2′-oxo-1′,2′-dihydrospiro[1-benzofuran-3,3′-indole]-6-carbonitrile (0.86 g, 74%) as a colorless solid which was carried forward without purification MS (ES+) m/z 263.0 (M+1).