C(=O)=O.CC(C)=O.[CH2:8]([Li])[CH2:9][CH2:10][CH3:11].[CH3:13][CH2:14][CH2:15][CH2:16][CH2:17][CH3:18].[C:19]([N:26](C1CCCCC1)[C@H](C=O)C)([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.O1CCCC1.CCOCC.CCCCCC.O>[C:22]([O:21][C:19]([NH:26][CH:15]([CH:14]=[CH2:13])[CH2:16][CH:17]1[CH2:11][CH2:10][CH2:9][CH2:8][CH2:18]1)=[O:20])([CH3:25])([CH3:24])[CH3:23]
To a stirred suspension of methyltriphenyl phosphonium bromide (10.97 g, 30.70 mmol) in anhydrous tetrahydrofuran (200 ml) at -78° C. (dry ice/acetone bath) under an argon atmosphere, was added n-butyl lithium (19.8 ml of a 1.55 M hexane solution) dropwise over the course of 5 minutes. After 10 minutes, the -78° C. bath was replaced with a 0° C. bath for one-half hour, at which time the resulting orange solution was cooled again to -78° C. The solution was then added dropwise by cannula to a stirred -78° C. solution of Boc-cyclohexylalaninal (27.91 mmol) in anhydrous tetrahydrofuran (30 ml) over the course of one-half hour. The mixture was then allowed to warm to room temperature during a 3 hour period after which water (150 ml) was added. Extraction with hexane (4×100 ml) provided a combined organic phase which was washed with brine (100 ml), dried (Na2SO4), and concentrated to give crude product. Chromatography with ether/hexane (1/9) provided the pure desired compound. Mass spectrum: (M+H)+ =254.
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