Asymmetric Mannich reaction between (S)-N-(tert-butanesulfinyl)-3,3,3-trifluoroacetaldimine and malonic acid derivatives. Stereodivergent synthesis of (R)- and (S)-3-amino-4,4,4-trifluorobutanoic acids
作者:Norio Shibata、Takayuki Nishimine、Naoyuki Shibata、Etsuko Tokunaga、Kosuke Kawada、Takumi Kagawa、José Luis Aceña、Alexander E. Sorochinsky、Vadim A. Soloshonok
DOI:10.1039/c3ob42425a
日期:——
diastereoselective Mannich additions of malonic acidderivatives to (SS)-N-(tert-butanesulfinyl)-3,3,3-trifluoroacetaldimine. In the presence of catalytic amounts of inorganic bases, n-BuLi or DMAP, the reaction gives the corresponding (R,SS)-β-aminomalonates in good yield and with diastereoselectivity up to 9/1 dr. In contrast, phosphazene bases favour the formation of the (S,SS)-diastereomer with selectivities
Organic base-catalyzed stereodivergent synthesis of (R)- and (S)-3-amino-4,4,4-trifluorobutanoic acids
作者:Norio Shibata、Takayuki Nishimine、Naoyuki Shibata、Etsuko Tokunaga、Kosuke Kawada、Takumi Kagawa、Alexander E. Sorochinsky、Vadim A. Soloshonok
DOI:10.1039/c2cc30627a
日期:——
base-catalyzed reaction of (S)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine with dialkyl malonates was found to be effective for synthesis of both (S,S(S)) and (R,S(S)) beta-aminomalonates in high yield with good to excellent diastereoselectivity (76-98% de). The products of this Mannich reaction provide direct access to beta-trifluoromethyl-beta-alanine of either (R) or (S) absolute configuration
Lewis acid activation of chiral 2-trifluoromethyl-1,3-oxazolidines. Application to the stereoselective synthesis of trifluoromethylated amines, α- and β-amino acids
The reaction of chiral 2-trifluoromethyl-1,3-oxazolidines with various silylated nucleophiles under Lewis acid activation provides a stereoselective route to functionalized α-trifluoromethylamines. This methodology was successfully applied to the diastereoselective synthesis of trifluoromethylated homoallylic and propargylic amines, trifluoromethylated α-amino nitrile, β-aminoketone and β-aminoester
Isothiourea-catalyzed formal enantioselective conjugate addition of benzophenone imines to β-fluorinated α,β-unsaturated esters
作者:Jerson E. Lapetaje、Claire M. Young、Chang Shu、Andrew D. Smith
DOI:10.1039/d2cc01936a
日期:——
isothiourea-catalyzed formal enantioselectiveconjugateaddition of 2-hydroxybenzophenone imine derivatives to α,β-unsaturated para-nitrophenyl esters has been developed. Investigations of the scope and limitations of this procedure showed that β-electron withdrawing substituents within the α,β-unsaturatedester component are required for good product yield, giving rise to a range of β-imino ester and amide derivatives
Operationally convenient asymmetric synthesis of (S)- and (R)-3-amino-4,4,4-trifluorobutanoic acid
作者:Vadim A. Soloshonok、Hironari Ohkura、Manabu Yasumoto
DOI:10.1016/j.jfluchem.2006.04.004
日期:2006.7
An asymmetric synthesis of (S)- and (R)-3-amino-4,4,4-trifluorobutanoic acidvia DBU-catalyzed asymmetric 1,3-proton shift transfer reaction of (Z)-3-[(R)-1-phenylethylamino]-4,4,4-trifluoro-N-[(R)-1-phenylethyl]but-2-enamide has been developed. The intermediate Schiff base (S,R′)-9 was found to be relatively configurationally stable under the highly basic reaction conditions allowing preparation of