1383121-33-2Relevant academic research and scientific papers
Enantioselective iridium-catalyzed hydrogenation of α-arylcinnamic acids and synthesis of (S)-equol
Yang, Shuang,Zhu, Shou-Fei,Zhang, Can-Ming,Song, Song,Yu, Yan-Bo,Li, Shen,Zhou, Qi-Lin
experimental part, p. 5172 - 5178 (2012/07/31)
By using iridium catalyst based on chiral spiro phosphine-oxazoline ligands, the hydrogenation of α-arylcinnamic acids was accomplished under ambient pressure and low catalyst loading (as low as 0.01 mol %), providing useful 2,3-diarylpropionic acids in high yields with excellent enantioselectivities (up to 99% ee). A catalytic enantioselective synthesis of (S)-equol with the present hydrogenation reaction as a key step was accomplished starting from commercially available starting materials in six steps with 48.4% overall yield.
Synthetic access to optically active isoflavans by using allylic substitution
Takashima, Yuji,Kaneko, Yuki,Kobayashi, Yuichi
experimental part, p. 197 - 207 (2010/03/03)
A general approach to the (S)- and (R)-isoflavans was invented, and efficiency of the method was demonstrated by the synthesis of (S)-equol ((S)-3), (R)-sativan ((R)-4), and (R)-vestitol ((R)-5). The key step is the allylic substitution of (S)-6a (Ar1=2,4-(MeO)2C6H3) and (R)-6b (Ar1=2,4-(BnO)2C6H3) with copper reagents derived from CuBr·Me2S and Ar2-MgBr (7a, Ar2=4-MeOC6H4; 7b, 2,4-(MeO)2C6H3; 7c, 2-MOMO-4-MeOC6H3), furnishing anti SN2′ products (R)-8a and (S)-8b,c with 93-97% chirality transfer in 60-75% yields. The olefinic part of the products was oxidatively cleaved and the Me and Bn groups on the Ar1 moieties was then removed. Finally, phenol bromide 9a and phenol alcohols 9b,c underwent cyclization with K2CO3 and the Mitsunobu reagent to afford (S)-3 and (R)-4 and -5, respectively.
