tert-Butyl (4R,6S)-6-(Bromomethyl)-2,2-dimethyl-1,3-dioxane-4-acetate → (4R-cis)-6-[(Acetyloxy)methyl]-2,2-dimethyl-1,3-dioxane-4-acetic acid, 1,1-dimethylethyl ester

HRID 1197947Notes

Reaction equation

Br[CH2:2][C@H:3]1[O:8][C:7]([CH3:10])([CH3:9])[O:6][C@@H:5]([CH2:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:4]1>C([O-])(=O)C.C([N+](CCCC)(CCCC)CCCC)CCC.CN1CCCC1=O>[C:7]([O:8][CH2:2][C@H:3]1[O:8][C:7]([CH3:10])([CH3:9])[O:6][C@@H:5]([CH2:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:4]1)(=[O:6])[CH3:9]

Participants

Conditions

Temperature: 90 °C

Procedure

Solid tetrabutylammonium acetate (62.1 g, 0.207 mole, commercially available reagent was used) was added in one portion to a stirring solution of the bromoacetonide obtained in step (c) above (22.3 g, 0.068 mole) in 1-methyl-2-pyrrolidinone (276 ml, commercially available HPLC grade, used as purchased) under an argon atmosphere. The resulting solution was stirred at 90° C. (external temperature) for 1 hour (after a few minutes the reaction mixture became brown in color) to complete the reaction. (The progress of the reaction was followed by TLC, Rf =0.48 for the title product; Rf =0.63 for the bromoacetonide starting material (Silica gel, Ethyl acetate:Hexane, 1:1, visualization by Ce(SO4)2 spray).) The reaction mixture was cooled to room temperature and poured into water (1.5 L) and extracted with heptane (4×800 ml). The organic layers were combined and washed with water, brine, dried over MgSO4, filtered and concentrated under reduced pressure to furnish 18.45 grams of a brown solid. It was dissolved in heptane (250 ml) and treated with neutral NORIT® (25 grams).

Workup

customthe reaction

Sources & evidence

ORD record: ord-4e525c88a2744dc08639418d622f29d2
Source dataset: uspto-grants-1994_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05278313

Reaction notes

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