Tributylstannane → tert-butyl 1-(chloromethyl)-7-cyano-1,2-dihydro-3H-benzo[e]indole-3-carboxylate

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Reaction Steps

A solution of 142 (6.78 g, 16.1 mmol) in dry benzene (80 mL) was treated with Bu3SnH (4.33 mL, 16.1 mmol), followed by AIBN (0.3 g, 1.8 mmol). The mixture was stirred at reflux under N2 for 2 h, then concentrated under reduced pressure, and the residue was chromatographed on silica gel. Elution with CH2Cl2 gave an oil that was triturated with iPr2O, to provide 143 contaminated with tert-butyl 7-cyano-1-methyl-1,2-dihydro-3H-benzo[e]indole-3-carboxylate. Two recrystallizations from CH2ClrPr2O gave pure tert-butyl 1-(chloromethyl)-7-cyano-1,2-dihydro-3H-benzo[e]indole-3-carboxylate (143) (4.49 g, 81%): mp 171-172° C.; 1H MR [(CD3)2SO] δ 8.55 (d, J=1.4 Hz, 1H), 8.18 (v br, 1H), 8.07 (d, J=8.7 Hz, 1H), 8.01 (d, J=8.9 Hz, 1H), 7.75 (dd, J=8.7, 1.7 Hz, 1 H), 4.34-4.25 (m, 1H), 4.21 (t, J=10.5 Hz, 1H), 4.09 (dd, J=11.3, 2.8 Hz, 1H), 4.03 (dd, J=11.1, 3.1 Hz, 1H), 3.93 (dd, J=11.1, 6.7 Hz, 1H), 1.55 (s, 9H). Anal. (C19H19ClN2O2.¼H2O) C, H, N.

Provenance & Evidence