196494-83-4

Upstream product

• 126378-42-5 4-methoxy-3-(trisopropylsilyl)pyridine 

Downstream Products

• 196494-88-9 (R)-2-(3-Chloro-propyl)-4-oxo-5-triisopropylsilanyl-3,4-dihydro-2H-pyridine-1-carboxylic acid (1R,2S)-2-(1-methyl-1-phenyl-ethyl)-cyclohexyl ester 
• 42922-10-1 septicine 
• 196494-85-6 (R)-2-(3-Hydroxy-propyl)-4-oxo-5-triisopropylsilanyl-3,4-dihydro-2H-pyridine-1-carboxylic acid (1R,2S)-2-(1-methyl-1-phenyl-ethyl)-cyclohexyl ester 

Relevant academic research and scientific papers

Enantiopure N-Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of (-)-Septicine and (-)-Tylophorine

A concise asymmetric synthesis of (-)-septicine (1) and (-)-tylophorine (2) was accomplished with a high degree of stereocontrol in eight and nine steps, respectively. Addition of 4-(1-butenyl)magnesium bromide to 1-acylpyridinium salt 3, prepared in situ from 4-methoxy-3-(triisopropylsilyl)pyridine and the chloroformate of (-)-trans-2-(α-cumyl)cyclohexanol, gave a 91% yield of diastereomerically pure dihydropyridone 7. Oxidative cleavage of 7 and subsequent reduction provided alcohol 6 in 81% yield. Conversion of 6 to the chloride followed by treatment with sodium methoxide gave indolizidinone 9 in high yield. Bromination and conjugate reduction of 9 with L-Selectride, and trapping the intermediate enolate with N-(5-chloro-2-pyridyl)triflimide, provided bromovinyl triflate 11. Palladium-catalyzed cross-coupling of excess (3,4-dimethoxyphenyl)zinc bromide and 11 gave (-)-septicine (1). On the basis of this synthesis, (-)-1 was assigned the R configuration. Reaction of 1 with vanadium(V) trifluoride oxide in TFA/CH2Cl2 effected oxidative coupling to give a 68% yield of (-)-tylophorine (2).