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The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines.

McGrath MJ, Bolm C - Beilstein J Org Chem (2007)

Bottom Line: Chiral base desymmetrisation of dimethyl sulfoximines could provide a general route to chiral, enantioenriched dialkyl sulfoximines with potential for use in asymmetric catalysis.Furthermore, a modified Horner-Emmons methodology was investigated.Simple chiral lithium amides afford products with enantiomeric excesses of up to 70%, illustrating that chiral base desymmetrisation of dimethyl sulfoximines is possible.

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Affiliation: Institut für Organische Chemie, Landoltweg 1, RWTH Aachen, Aachen 52074, Germany. matthew.mcgrath@oc.rwth-aachen.de

ABSTRACT

Background: Chiral base desymmetrisation of dimethyl sulfoximines could provide a general route to chiral, enantioenriched dialkyl sulfoximines with potential for use in asymmetric catalysis.

Results: Asymmetric deprotonation of N-trialkylsilyl dimethyl sulfoximines with either enantiomer of lithium N,N-bis(1-phenylethyl)amide in the presence of lithium chloride affords enantioenriched sulfoximines on electrophilic trapping. Ketones, ketimines, trialkylsilyl chlorides and activated alkyl halides may be used as electrophiles in the reaction. Furthermore, a modified Horner-Emmons methodology was investigated.

Conclusion: Simple chiral lithium amides afford products with enantiomeric excesses of up to 70%, illustrating that chiral base desymmetrisation of dimethyl sulfoximines is possible.

No MeSH data available.


The diamine (-)-sparteine and three chiral lithium amide bases.
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Figure 1: The diamine (-)-sparteine and three chiral lithium amide bases.

Mentions: Initial attempts at enantioselective deprotonation of TMS protected 1a using a complex of (-)-sparteine 4 (Figure 1) and n-BuLi as the chiral base and trapping the resulting anion with benzophenone gave the desilylated β-hydroxysulfoximine 2a with low enantiomeric excesses (Table 1, Entries 1 and 2).


The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines.

McGrath MJ, Bolm C - Beilstein J Org Chem (2007)

The diamine (-)-sparteine and three chiral lithium amide bases.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2100055&req=5

Figure 1: The diamine (-)-sparteine and three chiral lithium amide bases.
Mentions: Initial attempts at enantioselective deprotonation of TMS protected 1a using a complex of (-)-sparteine 4 (Figure 1) and n-BuLi as the chiral base and trapping the resulting anion with benzophenone gave the desilylated β-hydroxysulfoximine 2a with low enantiomeric excesses (Table 1, Entries 1 and 2).

Bottom Line: Chiral base desymmetrisation of dimethyl sulfoximines could provide a general route to chiral, enantioenriched dialkyl sulfoximines with potential for use in asymmetric catalysis.Furthermore, a modified Horner-Emmons methodology was investigated.Simple chiral lithium amides afford products with enantiomeric excesses of up to 70%, illustrating that chiral base desymmetrisation of dimethyl sulfoximines is possible.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut für Organische Chemie, Landoltweg 1, RWTH Aachen, Aachen 52074, Germany. matthew.mcgrath@oc.rwth-aachen.de

ABSTRACT

Background: Chiral base desymmetrisation of dimethyl sulfoximines could provide a general route to chiral, enantioenriched dialkyl sulfoximines with potential for use in asymmetric catalysis.

Results: Asymmetric deprotonation of N-trialkylsilyl dimethyl sulfoximines with either enantiomer of lithium N,N-bis(1-phenylethyl)amide in the presence of lithium chloride affords enantioenriched sulfoximines on electrophilic trapping. Ketones, ketimines, trialkylsilyl chlorides and activated alkyl halides may be used as electrophiles in the reaction. Furthermore, a modified Horner-Emmons methodology was investigated.

Conclusion: Simple chiral lithium amides afford products with enantiomeric excesses of up to 70%, illustrating that chiral base desymmetrisation of dimethyl sulfoximines is possible.

No MeSH data available.