tert-Butanesulfinamide | |
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2-Methyl-2-propanesulfinamide |
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Identifiers | |
CAS number | 146374-27-8 |
PubChem | 3382465 |
ChemSpider | 2627606 |
Jmol-3D images | Image 1 |
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Properties | |
Molecular formula | (CH3)3CS(O)NH2 |
Molar mass | 121.20 g/mole |
Appearance | white to off-white crystalline solid |
Melting point |
102 -105 °C |
(verify) (what is: / ?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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Infobox references |
tert-Butanesulfinamide is an organosulfur compound and a member of the class of sulfinamides . Both enantiomeric forms are commercially available and are relevant to the asymmetric synthesis of amines as a chiral ammonia equivalent.[1][2][3] This methodology was introduced in 1997 by Jonathan A. Ellman.[4]
Contents |
Chiral tert-butanesulfinamide can be prepared by enantioselective oxidation of inexpensive di-tert-butyl disulfide to the thiosulfinate followed by disulfide bond cleavage by lithium amide. In the original scope the chiral ligand used together with vanadyl acetylacetonate was prepared by condensing a chiral aminoindanol with 3,5-di-tert-butyl salicylaldehyde.
tert-Butanesulfinamide synthesis |
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Condensation with ketones and aldehydes yield the corresponding N-tert-butanesulfinyl aldimines and ketimines. These intermediates are more resistant to hydrolysis than other imines but more reactive towards nucleophiles. A nucleophile adds diastereoselectively over the imine group in an electrophilic addition with the tert-butanesulfinyl group acting as a chiral auxiliary. This tert-butanesulfinyl group is also a protecting group. On addition of hydrochloric acid the tert-butanesulfinyl group is removed forming the chiral primary ammonium salt or amine (from aldehyde precursor) or the chiral secondary amine (ketone precursor).
tert-Butanesulfinamide chiral amine synthesis |
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Typical nucleophiles are Grignard reagents, organozinc compounds, organolithium compounds, and enolates.
Chiral sulfinimines as intermediates for the asymmetric synthesis of amines have also been developed by Davis.[5]
tert-Butanesulfinamide has been used as an auxiliary in an asymmetric synthesis of cetirizine (more potent than the achiral drug) starting from p-chlorobenzaldehyde and phenylmagnesium bromide:[6]
Asymmetric cetirizine synthesis |
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