Novel Enantioselective Fluorinating Agents, (R)- and (S)-N-Fluoro-3-tertbutyl-7-nitro-3,4-dihydro-2H-benzo [e] [1,2] thiazine 1,1-Dioxides.
作者:Norio SHIBATA、Zhaopeng LIU、Yoshio TAKEUCHI
DOI:10.1248/cpb.48.1954
日期:——
Enantioselective fluorinating agents, (R)- and (S)-N-fluoro-3-tert-butyl-7-nitro-3, 4-dihydro-2H-benzo[e][1, 2]-thiazine 1, 1-dioxides (BNBT-F, 2) are readily prepared in 3 steps from racemic 3-tert-butyl-7-nitro-3, 4-dihydro-2H-benzo[e][1, 2]thiazine 1, 1-dioxides (5) via optical resolution and fluorination. These agents make accessible both enantiomers of optically active quaternary α-fluoro carbonyl compounds in modest to high enantioselectivities. X-ray crystallographic analysis of chiral 2 reveals a unique structure wherein the nitrogen atom is highly pyramidalized and fluorine occupies an axial position.
通过光学分离和氟化,可以从外消旋3-叔丁基-7-硝基-3,4-二氢-2H-苯并[e][1,2]噻嗪1,1-二氧化物(5)通过3个步骤轻松制备出手性氟化剂(R)-和(S)-N-氟-3-叔丁基-7-硝基-3,4-二氢-2H-苯并[e][1,2]噻嗪1,1-二氧化物(BNBT-F,2)。这些试剂可以以中等至高度的手性选择性获得光学活性四元α-氟羰基化合物的两种对映异构体。对手性2进行X射线晶体学分析,可以发现一种独特的结构,其中氮原子高度锥形化,氟占据轴向位置。