4-(Trifluoromethyl)phenylboronic acid → Methyl 4-((4'-(trifluoromethyl)biphenyl-3-yl)methyl)-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate

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Reaction Steps

The title compound was synthesized in four steps. First, tosyl protected methyl 4-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate (methyl 4-oxo-1-tosyl-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate) (1.50 g, 8.37 mmol) was reacted with 3-bromobenzylmagnesium bromide (15 mL, 3.75 mmol) according to General Procedure 3 to give exo olefin-containing compound (E)-methyl 4-(3-bromobenzylidene)-1-tosyl-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate, followed by coupling with 4-(trifluoromethyl)phenylboronic acid (0.178 g, 0.94 mmol) according to General Procedure 9.1 to give (E)-methyl 1-tosyl-4-((4′-(trifluoromethyl)biphenyl-3-yl)methylene)-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate, then tosyl deprotection according to General Procedure 10.1 to give (E)-methyl 4-((4′-(trifluoromethyl)biphenyl-3-yl)methylene)-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate. Hydrogenation of (E)-methyl 4-((4′-(trifluoromethyl)biphenyl-3-yl)methylene)-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate according to General Procedure 6 (with 5% Pd/C), then purification provided the title compound, which was used without purification in the next step. 0.047 g. 19F NMR (376 MHz, ACETONE-d6) δ ppm −63.27 (s, 3F); LCMS-MS (ESI−) 398.0 (M−H).

Provenance & Evidence