(4S,4'S)-2,2'-Cyclopropylidenebis[4-tert-butyl-4,5-dihydro oxazole],99%e.e. synthesis

Yield:195379-09-0 77%

Reaction Conditions:

with dmap;methanesulfonyl chloride;triethylamine in dichloromethane at 0 - 60; for 2.16667 - 12.1667 h;Product distribution / selectivity;

Steps:

5; 7-3; 8-3

Example 5; In a 100 mL Schlenk tube purged with nitrogen, 490 mg (1.49 mmol) of N,N'-bis[(S)-1-tert-butyl-2-hydroxyethyl]cyclopropane-1,1-dicarboxamide, 664 mg (6.56 mmol) of triethylamine, 18.2 mg (0.15 mmol) of 4-dimethylaminopyridine and 30 mL of dichloromethane were mixed and a homogeneous solution was obtained. The solution was cooled to 0°C. After 345 mg (3.01 mmol) of methanesulfonyl chloride was added dropwise to the solution over 10 minutes at the same temperature, the resulting mixture was heated to 20°C and stirred for 12 hours. After a saturated aqueous ammonium chloride solution was added thereto and stirred for 10 minutes at room temperature, the separation was conducted to obtain the oil layer. After the oil layer was washed with 20 mL of a saturated aqueous sodium hydrogen carbonate solution, a separation was conducted. The oil layer was dried over 5 g of anhydrous sodium sulfate. This reaction liquid was filtered and the obtained filtrate was concentrated. The residue was purified by column chromatography (alumina neutral, hexane:ethyl acetate = 10:1 (v/v)) to yield 339 mg of a white powder of 1,1-bis[2-[(4S)-tert-butyloxazoline]]cyclopropane. Yield: 77%. ¹H-NMR (δ: ppm, CD₃Cl₃ solvent, TMS standard) 4.22-4.10 (m, 4H), 3.85-3.79 (m, 2H), 1.52-1.48 (m, 2H), 1.29-1.24 (m, 2H), 0.86 (s, 18H); Example 7-3 ; According to the same manner as that described in Example 5, 344 mg of a white powder of 1,1-bis[2-[(4S)-tert-butyloxazoline]]cyclopropane was obtained except that 490 mg (1.49 mmol) of N,N'-bis[(S)-1-tert-butyl-2-hydroxyethyl]cyclopropane-1,1-dicarboxamide obtained in Example 7-2 was used. Yield: 79%.; Example 8-3 ; 2.70 g (8.22 mmol) of N,N'-bis[(S)-1-tert-butyl-2-hydroxyethyl]cyclopropane-1,1-dicarboxamide obtained in Example 8-2, 3.66 g (36.2 mmol) of triethylamine, 100 mg (0.82 mmol) of 4-dimethylaminopyridine and 30 mL of tetrahydrofuran were added and a homogeneous solution was obtained. The solution was cooled to 10°C. After 2.07 g (18.1 mmol) of methanesulfonyl chloride was added dropwise thereto over 10 minutes at the same temperature, the resulting mixture was heated to 60°C and stirred for 2 hours. After a saturated aqueous ammonium chloride solution was added thereto and stirred for 10 minutes at room temperature, the separation was conducted to obtain the oil layer. After the oil layer was washed with 20 mL of a saturated aqueous sodium hydrogen carbonate solution, a separation was conducted to obtain the oil layer. The oil layer was dried over 5 g of anhydrous sodium sulfate. This reaction liquid was filtered and the obtained filtrate was concentrated. The residue was purified by column chromatography (alumina neutral, hexane:ethyl acetate = 10:1 (v/v)) to yield 1.85 g of a white powder of 1,1-bis[2-[(4S)-tert-butyloxazoline]]cyclopropane. Yield: 77%.

References:

EP1698617,2006,A1 Location in patent:Page/Page column 12-13