Asymmetric Formal Synthesis of (+)-Catharanthine via Desymmetrization of Isoquinuclidine

Abstract

Although (+)-catharanthine is an attractive alkaloid for both clinical research and organic synthetic chemistry, only a limited number of approaches for its catalytic asymmetric synthesis exist. Herein, we describe a novel strategy for synthesizing a chiral intermediate of (+)-catharanthine via phosphoric acid-catalyzed asymmetric desymmetrization of a meso-isoquinuclidine possessing a 1,3-diol unit that was synthesized by a formal amide insertion reaction.

Monoterpenoid Indole Alkaloids with Promoting Neurite Growth from Tabernaemontana divaricata

“…The 13 C NMR and HSQC data for 5 indicated the presence of a methyl group, five methylenes, three sp 3 and four sp 2 methines, one sp 3 and four sp 2 quaternary carbons, a methyl ester, and an aldehyde group carbon (Table 1). Above data suggested 5 was similar to coronaridine [ 17 ] and catharanthine [ 18 ] except for one of methylene signals was replaced by aldehyde group ( δ C 183.1). In the HMBC spectrum, correlations from new signal δ H 10.01 to sp 2 signals of δ C 112.1 (C‐7), δ C 127.2 (C‐8), δ C 150.9 (C‐2), as well as correlations in benzene ring, indicated aldehyde group at aromatic ring.…”

Development of Novel Methodology Using Diazo Compounds and Metal Catalysts

“…13). The natural product has an impressive fused architecture that has attracted the attention of organic chemists and clinical researchers and can be transformed into vinblastine, 39) which is used to treat some human tumors.…”

Direct Conversion of 3-(2-Nitroethyl)-1H-Indoles into 2-(1H-Indol-2-yl)Acetonitriles

“…13 C NMR (101 MHz, Chloroform-d) δ 198.7, 160.0, 159.9, 138.2, 130.9, 129.1 (2C), 128.9, 128.8 (2C), 127.3 (2C), 126.5, 125.9, 120.3, 119.9, 117.9, 114.2 (2C), 112.3, 72.0, 55. 4 13 C NMR (101 MHz, DMSO-d 6 ) δ 199. 5, 162.3, 157.5, 156.6, 138.6, 130.6, 129.9, 128.6, 125.8, 125.3, 125.1, 121.1,…”

“…Derivatives of 1H-indole-2-acetic acid are common, naturally occurring indoline alkaloids with important bioactivities [1][2][3][4][5][6][7][8][9][10]. These compounds were used as key intermediates in total syntheses of several natural products and nonnatural pharmaceutical agents [11][12][13][14][15][16][17].…”