Isopropyltriphenylphosphonium iodide → Phosphorane, (1-methylethylidene)triphenyl-

Reaction equation

C([Li])CCC.[I-].[CH:7]([P+:10]([C:23]1[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1)([C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)([CH3:9])[CH3:8]>CCCCCC.O1CCCC1>[C:23]1([P:10]([C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=2)([C:17]2[CH:18]=[CH:19][CH:20]=[CH:21][CH:22]=2)=[C:7]([CH3:9])[CH3:8])[CH:24]=[CH:25][CH:26]=[CH:27][CH:28]=1

Participants

Procedure

A solution of n-butyllithium in hexane was added to a suspension of isopropyltriphenylphosphonium iodide in tetrahydrofuran to obtain a solution of 12.5×10-3M of triphenylisopropylidene phosphorane in tetrahydrofuran and 20 ml of the solution were added to a solution of 1.35 g of the product of Step B in 25 ml of tetrahydrofuran. After stirring at 0° C. for one hour and then at room temperature for one hour, the mixture was diluted with 10 ml of water and was extracted with ether. The extract was dried and evaporated to dryness under reduced pressure. The residue was chromatographed over silica to obtain the expected product in a 50 to 60% yield which after crystallization from cyclohexane had a specific rotation of [α]D =-55.5° (c=20.25 in CHCl3).