5,5-Dimethyl-2-phenylamino-2-oxazoline as an effective chiral auxiliary for asymmetric alkylations

Tetrahedron Letters

Volumn 48, Issue 44, 2007, Pages 7834-7837

  Le, Thanh Nguyen ^a   Nguyen, Quynh Pham Bao ^a   Kim, Jae Nyoung ^b   Kim, Taek Hyeon ^a  

^a Center for Functional Nano Fine Chemicals   (South Korea)

^b Chonnam National University   (South Korea)

Author keywords

[No Author keywords available]

Indexed keywords

5,5 DIMETHYL 2 PHENYLAMINO 2 OXAZOLINE; 5,5 DIPHENYL 2 PHENYLAMINO 2 OXAZOLINE; ESTER DERIVATIVE; METHYL GROUP; OXAZOLINE DERIVATIVE; UNCLASSIFIED DRUG; VALINE;

ALKYLATION; ARTICLE; CHIRALITY; REACTION ANALYSIS; STEREOCHEMISTRY; SYNTHESIS;

EID: 34948849179     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2007.09.001     Document Type: Article

References (27)

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21. General procedure for asymmetric alkylation of N-acyl 5,5-disubstituted 2-phenylimino-2-oxazolidines. To a dry round-bottomed flask under nitrogen was added compound 7 (0.1 g) in anhydrous THF (4 mL). The solution was cooled to -78 °C. A solution of lithium bis(trimethylsilylamide) (LiHMDS) in THF (1.0 M, 2-4 equiv) was added dropwise, and the solution was allowed to stir for 30 min. The mixture was treated with halide (3-8 equiv). After stirring for 30 min at -78 °C and 1 h at 0 °C, the reaction mixture was quenched with saturated ammonium chloride (4 mL) and water (20 mL) and extracted with ether. The combined extracts were dried over magnesium sulfate, filtered, and concentrated. HPLC analysis of the crude product revealed the isomer ratios. Purification by flash chromatography (hexane/EtOAc 8:2) afforded the major diastereomer 8.Compound 8a:
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