A highlyefficient synthesis of novel spirocyclic benzoxazine‐indenes from benzoxazine and alkynes via iminedirected C–H activation/annulation using rhodium catalyst was reported. The methodology could be applied to various benzoxazines and alkynes, giving the corresponding spiro indenyl benzoxazine as spirocycle products in good yields.
First I2–K2CO3-promoted sequential C–N and C–O bond forming approach for one-pot synthesis of 1,4-benzoxazines
作者:Sunil K. Singh、Anil K. Bajpai、Rajesh Saini
DOI:10.1016/j.tetlet.2013.10.092
日期:2013.12
system for the one-potsynthesis of 3-aryl-2H-benz[1,4]oxazine viarapid CN and C–O bond formation. No by-product formation, operational simplicity, ambient temperature, and high yield (85–94%) are the attractive features of the envisaged reaction. The reported one-potsynthesis of 1,4-benzoxazine involves the application of I2–K2CO3 catalyst system for the first time and proceeds via in situ imine
已经发现,I 2 –K 2 CO 3组合是一种通过快速CN和C–O一锅合成3-芳基-2 H-苯并[1,4]恶嗪的有效,可重复使用和廉价的催化剂体系。键的形成。没有副产物的形成,操作简便,环境温度和高产率(85-94%)是预期反应的吸引人的特征。已报道的1,4-苯并恶嗪的一锅法合成首次涉及I 2 -K 2 CO 3催化剂体系的应用,并通过原位亚胺形成,随后进行分子内环转化级联反应进行。
A series of tunable and regenerable biomimetic hydrogen sources, 4,5-dihydropyrrolo[1,2-a]quinoxalines, have been synthesized and applied in biomimetic asymmetric hydrogenation of 3-aryl-2H-benzo[b][1,4]oxazines and 1-alkyl-3-aryl-quinoxalin-2(1H)-ones, providing the chiral amines with up to 92% and 89% ee, respectively.
合成了一系列可调和可再生的仿生氢源4,5-二氢吡咯并[1,2- a ]喹喔啉,并将其用于3-芳基-2 H-苯并[ b ] [1,4]的仿生不对称加氢。恶嗪和1-烷基-3-芳基-喹喔啉-2(1 H)-酮,分别为手性胺提供高达92%和89%的ee。
Highly Enantioselective SPINOL-Derived Phosphoric Acid Catalyzed Transfer Hydrogenation of Diverse C=N-Containing Heterocycles
作者:Yiliang Zhang、Rong Zhao、Robert Li-Yuan Bao、Lei Shi
DOI:10.1002/ejoc.201500330
日期:2015.5
A highly efficient and enantioselectivehydrogenation of diversely substituted C=N-containing heterocyclic compounds such as 3-aryl-1,4-benzoxazines and 2-arylquinolines was experimentally explored by using 1,1′-spirobiindane-7,7′-diol-derived chiral phosphoric acids as the catalyst. This method provides straightforward access to the corresponding tetrahydroquinolines and dihydro-2H-1,4-benzothiazines