Oxidation of cycloalkan[b]indoles with iodine pentoxide(I2O5).

Enantioselective total synthesis of the indole alkaloid 16-episilicine

“…Finally, the exchange of the Boc protecting group for methyl furnished (À)-16-episilicine, thus completing the first synthesis of this natural product. The 1 H and 13 C NMR data of our synthetic 16-episilicine were in complete agreement with those previously reported 5b for the alkaloid. However, the specific rotation of our synthetic material, [a] D 22 À20 (c 1.0 in CHCl 3 ), although coincident in its absolute value with that reported for 16-episilicine, [a] D 22 +20 (c 1.0 in CHCl 3 ), 5 had the opposite sign.…”

A Synthetic Approach to Ervatamine-Silicine Alkaloids. Enantioselective Total Synthesis of (−)-16-Episilicine

“…Deprotection of the indole nitrogen under smooth conditions, followed by a catalytic debenzylation in the presence of (Boc) 2 O led to the N -Boc protected piperidine derivative 19 . A chemoselective oxidation with I 2 O 5 installed the 2-acylindole carbonyl group. Finally, removal of the Boc protecting group followed by methylation furnished (−)-16-episilicine, thus completing the first synthesis of this natural product.…”

Enantiotopos‐Selective CH Oxygenation Catalyzed by a Supramolecular Ruthenium Complex

“…Indeed the instability of alcohols related to 6 a has been reported earlier. [31] In the present work, a reduced derivative of 7 a was isolated when subjecting ketone 5 a to reducing conditions (see SI). It appears as if the ring opening was favored by electron-withdrawing groups at the oxindole ring.…”