Enantioselective Synthesis of Glutarimide Alkaloids Cordiarimides A, B, Crotonimides A, B, and Julocrotine

Abstract

Five glutarimide alkaloids cordiarimide A (5), cordiarimide B (6), crotonimide A (3), crotonimide B (4), and julocrotine (2) have been synthesized starting from Boc-L-glutamine (7). The benzylic alcohol chiral centre of cordiarimides B (6) has been established in 6 : 1 diastereoselectivity by catalytic asymmetric hydrogenation using Zhou's catalytic system Pd(CF(3)CO(2))(2)/(R,R)-Me-DuPhos.National Natural Science Foundation of China[20832005]; National Basic Research Program (973 Program) of China[2010CB833200

Rapid separation of fatty acids using a poly(vinyl alcohol) coated capillary in nonaqueous capillary electrophoresis with contactless conductivity detection

“…CE is an alternative to LC, which is usually carried out in fully aqueous media, but NACE has also been reported, in particular for the determination of compounds that are insoluble in water. Several reviews are available, which comprehensively discuss the fundamentals and applications of NACE [24][25][26][27][28][29]. The use of C 4 D in NACE has also been carried out.…”

Glutarimide Alkaloids Through Multicomponent Reaction Chemistry

“…Next, we were keen to apply the same synthetic approach to the structurally related natural products crotonimides A, B and C. [13,[22][23] For these three alkaloids the amino-component was the (S)-(-)-4-methoxy-α-methylbenzylamine auxiliary, whereas the carboxylic acids were propionic acid for crotonimide A, isobutyric acid for crotonimide B and benzoic acid for crotonimide C (Scheme 4).…”

“…[10] In 2011, a six step synthesis starting from L-glutamic acid was described. Moreover, a stereoselective synthesis for julocrotine and structurally related glutarimide alkaloids was reported based on Boc-L-glutamine [13] (Figure 1). [12] In this case, the key amine intermediate was used as the amine component of an Ugi reaction, but with limited diversity.…”

Homogeneous palladium-catalyzed asymmetric hydrogenation

“…Furthermore, this method could be used as the key step in the synthesis of chiral crotonimide B which has potential for cancer chemoprevention. 37 Several other ketones have been examined to further expand the utility of this Pd-catalyzed asymmetric hydrogenation of ketones, but lower enantioselectivities were observed. In 2010, Zhang et al synthesized a new class of atropisomeric diphosphine ligands with a wide range of dihedral angles (Scheme 20).…”