196929-95-0Relevant academic research and scientific papers
One-pot asymmetric synthesis of tert-butanesulfinyl-protected amines from ketones by the in situ reduction of tert-butanesulfinyl ketimines
Borg, George,Cogan, Derek A.,Ellman, Jonathan A.
, p. 6709 - 6712 (1999)
A one-pot method for the asymmetric synthesis of tert-butanesulfinyl-protected amines is described. The ketones 2 are condensed with (R)-tert-butanesulfinamide 1 and the tert-butanesulfinyl imine intermediates reduced in situ with NaBH4 to affo
Diastereomers of N-α-phenylethyl-t-butylsulfinamide: Absolute configurations and predominant conformations
Petrovic, Ana G.,Polavarapu, Prasad L.,Drabowicz, Jozef,Lyzwa, Piotr,Mikolajczyk, Marian,Wieczorek, Wanda,Balinska, Agnieszka
, p. 3120 - 3129 (2008)
(Chemical Equation Presented) N-α-Phenylethyl-t-butylsulfinamide is a complicated system for determining molecular stereochemistry because of numerous possibilities for assigning the absolute configuration and a predominant conformation. Two diastereomers
A versatile Ru catalyst for the asymmetric transfer hydrogenation of both aromatic and aliphatic sulfinylimines
Pablo, Oscar,Guijarro, David,Kovacs, Gabor,Lledos, Agusti,Ujaque, Gregori,Yus, Miguel
, p. 1969 - 1983 (2012/03/26)
A highly efficient Ru catalyst based on an achiral, very simple, and inexpensive amino alcohol ligand (2-amino-2-methylpropan-1-ol) has been developed for the asymmetric transfer hydrogenation (ATH) of chiral N-(tert-butylsulfinyl)imines. This complex is able to catalyze the ATH of both aromatic and the most challenging aliphatic sulfinylimines by using isopropyl alcohol as the hydrogen source. The diastereoselective reduction of aromatic, heteroaromatic, and aliphatic sulfinylketimines, including sterically congested cases, over short reaction times (1-4 h), followed by desulfinylation of the nitrogen atom, affords the corresponding highly enantiomerically enriched (ee up to >99%) α-branched primary amines in excellent yields. The same ligand was equally effective for the synthesis of both (R)- and (S)-amines by using the appropriate absolute configuration in the iminic substrate. DFT mechanistic studies show that the hydrogen-transfer process is stepwise. Moreover, the origin of the diastereoselectivity has been rationalized.
Recycling the tert-butanesulfinyl group in the synthesis of amines using tert-butanesulfinamide
Wakayama, Masakazu,Ellman, Jonathan A.
supporting information; experimental part, p. 2646 - 2650 (2009/08/15)
A practical process for recycling the tert-butanesulfinyl group upon deprotection of N-tert-butanesulfinyl amines has been achieved. Treatment of N-tert-butanesulfinyl amines with HCl in cyclopentyl methyl ether results in complete conversion to tert-butanesulfinyl chloride and the corresponding amine hydrochloride salt, which is isolated by filtration in analytically pure form and in quantitative yield. Treatment of the resulting sulfinyl chloride solution with aqueous ammonia then provides analytically pure tert-butanesulfinamide in 97% yield. Alternatively, the tert-butanesulfinyl chloride solution can be treated with ethanol and catalytic quinidine as a sulfinyl transfer catalyst to provide a cyclopentyl methyl ether solution of ethyl tert-butanesulfinate with 88% ee. Addition of NaNH2 in ammonia followed by simple trituration of the product with octane provides tert-butanesulfinamide with 99% ee and in 67% overall isolated yield based upon the starting N-tert-butanesulfinyl amine.
Synthesis of highly enantiomerically enriched amines by the diastereoselective addition of triorganozincates to N-(tert-butanesulfinyl)imines
Almansa, Raquel,Guijarro, David,Yus, Miguel
experimental part, p. 2484 - 2491 (2009/04/11)
The reaction of triorganozincates with (R)-N-(tert-butanesulfinyl) imines gives the expected α-branched sulfinamides in good to excellent yields with diastereomeric ratios of up to 98:2. The N-sulfinyl group of the products can be easily removed by acidic treatment, affording the corresponding chiral primary amines in enantiomeric excesses of up to 96%. The reactivity and the selectivity shown by the triorganozincates are different from the ones observed with the corresponding Grignard reagents, which allows, in several cases, the preparation of both enantiomers of an amine from the same imine substrate. When mixed triorganozincates are used, one can take advantage of the slow transfer rate of the methyl group to use it as a non-transferable one. Both aromatic and aliphatic aldimines, as well as activated ketimines, are good substrates for these addition reactions.
One-pot asymmetric synthesis of either diastereomer of tert-butanesulfinyl- protected amines from ketones
Tanuwidjaja, Jessica,Peltier, Hillary M.,Ellman, Jonathan A.
, p. 626 - 629 (2007/10/03)
A one-pot method for the asymmetric synthesis of tert-butanesulfinyl- protected amines is described. Condensation of aryl alkyl and dialkyl ketones with tert-butanesulfinamide followed by in situ reduction with the appropriate reagent provides either dias
Reversal of diastereofacial selectivity in hydride reductions of N-tert-butanesulfinyl imines
Colyer, John T.,Andersen, Neil G.,Tedrow, Jason S.,Soukup, Troy S.,Faul, Margaret M.
, p. 6859 - 6862 (2007/10/03)
A variety of N-tert-butanesulfinyl imines were reduced with NaBH 4 in THF containing 2% water to provide the corresponding secondary sulfinamides in high yield and diastereoselectivity. By using the same sulfinyl imine starting materials and changing the reductant to L-Selectride, the stereoselectivity could be efficiently reversed to afford the opposite product diastereomer in high yield and selectivity.
