Preparation of 7-Halo-indoles by Thallation of N-Formylindoline and Their Attempted Use for Synthesis of the Right-Hand Segment of Chloropeptin

Catalytic Enantioselective Desymmetrisation as a Tool for the Synthesis of Hodgkinsine and Hodgkinsine B

“…As a simple model system, we elected to couple acid 22 with 7‐haloindolines,24 but regrettably the coupling was hampered by the steric bulk of the ortho‐ halide. Investigation of numerous amide coupling agents identified that optimal yields were obtained when the acid 22 was activated as the acid chloride.…”

A Diastereodivergent Synthetic Strategy for the Syntheses of Communesin F and Perophoramidine

“…15 To our delight, the cleavage of both formyl and o -nitrobenzyl groups was achieved using 20% aq NaOH at 75 °C to deliver aminal 19 in 50% yield. 16 Aminal 19 was advanced by Funk in his synthesis of perophoramidine, 6o thus completing our formal synthesis of the natural product.…”

“…The indoline methyl group was oxidized to a formyl functionality using PDC to produce 27 in 62% yield (93% yield based on recovered starting material) . To our delight, the cleavage of both formyl and o -nitrobenzyl groups was achieved using 20% aq NaOH at 75 °C to deliver aminal 19 in 50% yield . Aminal 19 was advanced by Funk in his synthesis of perophoramidine, thus completing our formal synthesis of the natural product.…”

Pd/C-Catalyzed Reductive Formylation of Indoles and Quinolines Using Formic Acid

“…When the carbonyl group is used as a directing group on indolines, however, the C-7-selective product is observed as the major product. 7,8 The nitrogen can then be deprotected by hydrolysis to obtain a 7-substituted indoline which can be aromatized to obtain the corresponding C-7substituted indole (Scheme 2). 8 Previously, N-formylindolines were synthesized by the formylation of indolines, which in turn were synthesized from indoles by reduction, in separate steps.…”

“…7,8 The nitrogen can then be deprotected by hydrolysis to obtain a 7-substituted indoline which can be aromatized to obtain the corresponding C-7substituted indole (Scheme 2). 8 Previously, N-formylindolines were synthesized by the formylation of indolines, which in turn were synthesized from indoles by reduction, in separate steps. 9 Heterogeneous catalytic hydrogenation is a very efficient and powerful tool for achieving controlled reduction of various organic compounds.…”