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 acid derivatives 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
无机以及有机碱催化被发现是有效的丙二酸衍生物的非对映选择性曼尼希增补(小号小号) - ñ - (叔-butanesulfinyl)-3,3,3- trifluoroacetaldimine。在催化量的无机碱,n- BuLi或DMAP的存在下,反应以高收率和高达9/1 dr的非对映选择性产生相应的(R,S S)-β-氨基丙二酸酯。相反,磷腈碱有利于(S,S S)-非对映异构体,选择性高达99/1。简单地为曼尼希加成反应选择合适的碱催化剂,使我们能够在相应的β-氨基丙二酸酯水解和脱羧后获得对映体纯的(R)-或(S)-构型的3-氨基-4,4,4-三氟丁酸。 。