Diisopropylamine → Lithium diisopropylamide

HRID 1781544Notes

Reaction equation

[CH:1]([NH:4][CH:5]([CH3:7])[CH3:6])([CH3:3])[CH3:2].C([Li:12])CCC.Br[CH2:14][CH2:15][CH:16]([CH2:21][C:22]([CH3:46])=[CH:23][CH2:24][C:25]1[C:26]([O:38][Si:39]([C:42]([CH3:45])([CH3:44])[CH3:43])([CH3:41])[CH3:40])=[C:27]2[C:31](=[C:32]([CH3:36])[C:33]=1[O:34][CH3:35])[CH2:30][O:29][C:28]2=[O:37])[C:17]([O:19][CH3:20])=[O:18].[Li+].CC([N-]C(C)C)C>C1COCC1>[CH:1]([N-:4][CH:5]([CH3:7])[CH3:6])([CH3:3])[CH3:2].[Li+:12].[CH3:20][O:19][C:17]([C:16]1([CH2:21][C:22]([CH3:46])=[CH:23][CH2:24][C:25]2[C:26]([O:38][Si:39]([C:42]([CH3:45])([CH3:43])[CH3:44])([CH3:41])[CH3:40])=[C:27]3[C:31](=[C:32]([CH3:36])[C:33]=2[O:34][CH3:35])[CH2:30][O:29][C:28]3=[O:37])[CH2:14][CH2:15]1)=[O:18]

Participants

Conditions

Temperature: -70 °C

Procedure

A solution of lithium diisopropyl amide was prepared from diisopropyl amine (2.24 ml) and n-butyllithium (6.4 ml, 2.5N) in THF (60 ml) and cooled to -70° C. Methyl 2-(2-bromoethyl)-6-(4-t-butyldimethylsiloxy-1,3-dihydro-6-methoxy-7-methyl-3-oxoisobenzofuran -5-yl)-4-methyl-hex-4-enoate (2.66 g) in THF (12 ml was added to the LDA solution over 2 min. The reaction mixture was stirred for 50 min at -65° C. to -50° C. and quenched in water. Extraction with ethyl acetate and flash chromatography (silica gel, 20-30% ethyl acetate/hexane) gave 1-[4-(4-t-butyldimethylsiloxy-1,3-dihydro-6-methoxy-7-methyl-3-oxoisobenzofuran -5-yl)-2-methyl-but-2-enyl] cyclopropane carboxylic acid methyl ester (1.34 g).

Workup

customquenched in water
extractionExtraction with ethyl acetate and flash chromatography (silica gel, 20-30% ethyl acetate/hexane)

Sources & evidence

ORD record: ord-0ae8071f8fc94140b0001a99db3d857b
Source dataset: uspto-grants-1997_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05633279

Reaction notes

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