Diversity-Oriented Asymmetric Catalysis (DOAC): Stereochemically Divergent Synthesis of Thiochromanes Using an Imidazoline–Aminophenol–Nickel-Catalyzed Michael/Henry Reaction
作者:Takayoshi Arai、Yushi Yamamoto
DOI:10.1021/ol500361w
日期:2014.3.21
The (S,S)-diphenylethylenediamine-derived imidazoline-aminophenol-Ni complex catalyzed tandem asymmetric Michael/Henry reaction of 2-mercaptobenzaldehydes with beta-nitrostyrenes to give the corresponding (2S,3R,4R)-2-aryl-3-nitrothiochroman-4-ols in up to 99% diastereoselectivity with 95% ee was demonstrated in diversity-oriented asymmetric catalysis. Reduction of the nitro group of the chiral thiochromanes gave a new series of (2S,3R,4R)-3-amino-2-arylthiochroman-4-ols with retention of the strereoselectiyity.
Chiral Bis(imidazolidine)iodobenzene (I-Bidine) Organocatalyst for Thiochromane Synthesis Using an Asymmetric Michael/Henry Reaction
Bis(imidazolidine)iodobenzene (I-Bidine) was designed as an organocatalyst based on previously reported imidazolidine- or oxazolidine-containing chiral metal catalysts. I-Bidine showed catalytic activity for the Michael/Henry reaction of thiosalicyl aldehydes with nitroalkenes to give optically active thiochromanes with moderate enantiomericexcesses.
Synthesis of 2,3,4-Trisubstituted Thiochromanes using an Organocatalytic Enantioselective Tandem Michael-Henry Reaction
作者:Rajasekhar Dodda、Joshua J. Goldman、Tanmay Mandal、Cong-Gui Zhao、Grant A. Broker、Edward R. T. Tiekink
DOI:10.1002/adsc.200700331
日期:2008.3.7
Enantioenriched 2,3,4-trisubstituted thiochromanes have been synthesized by using a cupreine-catalyzed tandem Michael addition-Henry reaction between 2-mercaptobenzaldehydes and beta-nitrostyrenes. Good diastereoselectivities and enantioselectivities were obtained for the title compounds, which may be further improved through a single recrystallization (up to 98% de and> 99% ee).
通过使用 2-巯基苯甲醛和 β-硝基苯乙烯之间的铜催化串联迈克尔加成-亨利反应合成了对映体富集的 2,3,4-三取代硫代苯并二氢吡喃。标题化合物获得了良好的非对映选择性和对映选择性,可以通过单次重结晶进一步改进(高达 98% de 和 > 99% ee)。