2,2-Dimethoxypropane → (3aR,4R,9bR)-benzyl 4-(methoxymethyl)-2,3,3a,4,5,9b-hexahydro-1H-pyrrolo[3,2-c]quinoline-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

In a 120 mL stainless autoclave were charged benzyl 3-(2-methoxy-1-(phenylamino)ethylidene)-2-oxopyrrolidine-1-carboxylate (1.50 g) [mw. 366.41, 4.1 mmol], cyanuric acid (0.53 g) [mw. 129.07, 4.1 mmol] and RuBr2[(s,s)-ptbp-skewphos](pica) (42.4 mg) [mw. 1033.94, 0.041 mmol]synthesized in Reference Example 52, and the system was substituted with argon. To deaeration-treated dehydrated acetone (55 mL) was added 2,2-dimethoxypropane (1.5 mL) [mw. 104.15, d=0.85, 12.3 mmol, 3.0 eq.] and the mixture was added to the autoclave by argon pressure supply. Furthermore, 2,2-dimethoxypropane was rinsed with dehydrated acetone (5 mL), and added by argon pressure supply. Hydrogen was filled therein to 5 MPa, and the mixture was stirred at a reaction temperature of 60° C. for 46 hr. The reaction mixture was cooled to room temperature and depressurized. Quantification by high performance liquid chromatography confirmed that the starting material, benzyl 3-(2-methoxy-1-(phenylamino)ethylidene)-2-oxopyrrolidine-1-carboxylate, remained, the reaction intermediate, benzyl 3-(2-methoxy-1-(phenylamino)ethyl)-2-oxopyrrolidine-1-carboxylate, was not more than 1%, and the resultant product, (3aR,4R,9bR)-benzyl 4-(methoxymethyl)-2,3,3a,4,5,9b-hexahydro-1H-pyrrolo[3,2-c]quinoline-1-carboxylate, was also not more than 1%.

Provenance & Evidence