Examination of Synthetic Routes to Monosubstituted Diimides. II. Synthesis of t-Butyl Aryl- and Acylazoformates. Acid-Induced Cleavage of the Thionocarbo-t-butoxy Group1,2
We report here the synthesis of a novel family of N-CF3 hydrazines from a direct way involving the available and cheap Langlois reagent (CF3SO2Na). These derivatives have shown very high stability whatever the conditions used and are excellent precursors for building previously inaccessible N-CF3 functionalized compounds, such as substituted hydrazides, hydrazine-amino-acids, hydrazones, N-aziridines
我们在此报告了一种新型N -CF 3肼家族的合成,该方法涉及可用且廉价的朗格洛伊试剂 (CF 3 SO 2 Na)的直接方式。无论使用何种条件,这些衍生物都显示出非常高的稳定性,并且是构建以前无法获得的N -CF 3官能化化合物的优秀前体,例如取代酰肼、肼氨基酸、腙、N-氮丙啶和吡唑。
[4+2] Cycloaddition of Ketenes with<i>N</i>-Benzoyldiazenes Catalyzed by N-Heterocyclic Carbenes
作者:Xue-Liang Huang、Lin He、Pan-Lin Shao、Song Ye
DOI:10.1002/anie.200804487
日期:2009.1
Enantioselectivity switch: A catalytic enantioselective [4+2] cycloaddition reaction of alkylarylketenes with N‐aryl‐N′‐benzoyldiazenes or N,N′‐dibenzoyldiazenes to give 1,3,4‐oxadiazin‐6‐ones 1 was developed by employing N‐heterocyclic carbene (NHC) catalysts. The enantioselectivities could be switched for most reactions by changing the substituents on the NHC catalyst. TBS=tert‐butyldimethylsilyl
of electrophilic azo reagents with NHC-boranes leads to the formation of NHC complexes of mono- and bis-hydrazino boranes with N−N−B and N−N−B−N−N chains. Steric hindrance on the carbene (primarily) and on the azo reagent (somewhat less) is crucial for the reactivity. Bis-hydrazino borane complexes with two different hydrazine arms could be obtained via sequential additions.