1,2 Asymmetric induction in the TiCl4 mediated alkylation of α-methyl-β-silyloxy ketones with Grignard reagents

Tetrahedron Letters

Volumn 38, Issue 21, 1997, Pages 3785-3788

  Bartoli, Giuseppe ^a   Bosco, Marcella ^a   Sambri, Letizia ^a   Marcantoni, Enrico ^b  

^a UNIVERSITY OF BOLOGNA   (Italy)

^b Dipartimento di Scienze Chimiche dell'Universita   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

ALKANEDIOL DERIVATIVE;

ALKYLATION; ARTICLE; DRUG SYNTHESIS; IN VITRO STUDY; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0030965844     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)00735-1     Document Type: Article

References (28)

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23. 4 (2.6 mmol, 1.3 eq) was added to a solution of the α-methyl-β-silyloxy ketone (2 mmol) in dry toluene, at 0°C. The reaction was allowed to reach room temperature, and stirred until transmetallation was complete, (10-15 min. for 1c,d and 1h for 1e). The reaction was then cooled at -78°C and the appropriated Grignard reagent (6 mmol, 3 eq) was added dropwise. After stirring 1h at -78°C, the reaction was left to reach room temperature and then quenched with diluted aqueous HCl. The usual work-up gave the crude product, that was purified by flash cromatography on silica-gel.
24. Descriptors R*, S* indicate that diastereomeric compounds are obtained as racemates. We prefer this terminology to avoid the ambiguities that could arise from the sin-anti or erithro-threo ones.
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