Fig. 8: Total synthesis of phyllanthine (5) and 4-epi-securitinine (52). | Nature Communications

Fig. 8: Total synthesis of phyllanthine (5) and 4-epi-securitinine (52).

From: Collective total synthesis of C4-oxygenated securinine-type alkaloids via stereocontrolled diversifications on the piperidine core

Fig. 8

a Reagents and conditions: (a) 45 (1.5 equiv), LiHMDS (1.2 equiv), THF, –78 °C to –40 °C, 79%; (b) K-selectride (1.2 equiv), THF, –78 °C, 84%; (c) 4-nitrobenzoic acid (2.0 equiv), PPh3 (1.5 equiv), DIAD (2.0 equiv), THF, 0 °C to 23 °C; (d) K2CO3 (3.0 equiv), MeOH, –78 °C, 99% (2 steps); (e) Me3OBF4 (3.0 equiv), proton-sponge (4.0 equiv), CH2Cl2, 0 °C to 23 °C, 91%; (f) TBAF (1.0 equiv), THF, 23 °C, 84%; (g) TFA:CH2Cl2 (1:1 v/v), 23 °C; (h) Et3N:MeOH (1:2 v/v), 50 °C, 93% (2 steps); (i) MsCl (3.0 equiv), Et3N (6.0 equiv), CH2Cl2, 0 °C, 90%; (j) [Ir{dF(CF3)ppy}2(dtbpy)]PF6 (0.01 equiv), PhSH (1.0 equiv), blue LED (427 nm), MeOH, 23 °C, 51 63% and 50 15%; (k) MsCl (3.0 equiv), Et3N (6.0 equiv), CH2Cl2, 0 °C, 72%; b Rationale for the diastereoselective formation of 46. LiHMDS lithium bis(trimethylsilyl)amide, DIAD diisopropyl azodicarboxylate.

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