Iodine-Catalyzed, Stereo- and Regioselective Synthesis of 4-Arylidine-4H-benzo[d][1,3]oxazines and their Applications for the Synthesis of Quinazoline 3-Oxides
作者:Wen-Chun Lee、Ho-Chuan Shen、Wan-Ping Hu、Wei-Sheng Lo、Chebrolu Murali、Jaya Kishore Vandavasi、Jeh-Jeng Wang
DOI:10.1002/adsc.201200018
日期:2012.8.13
4-Benzylidene-2-aryl-4H-benzo[d][1,3] oxazines have been synthesized with high stereoselectivity and regioselectivities from 2-alkynylbenzamides in the presence of a catalytic amount of I2. In the reaction mechanism, iodine plays a key role in two different aspects as a catalyst, such as to activate the alkyne with the iodinium donor which triggers the cascade, and then as a proper acid source to facilitate
在催化量的I 2存在下,由2-炔基苯甲酰胺以高的立体选择性和区域选择性合成了4-苄基-2-芳基-4 H-苯并[ d ] [1,3]恶嗪。在反应机理中,碘在两个不同方面起着催化剂的关键作用,例如用引发级联反应的碘供体活化炔烃,然后作为适当的酸源以促进催化剂的回收。苯并恶嗪已经被用作直接一步合成喹唑啉3-氧化物衍生物的潜在底物。
Synthesis of 3,1-Benzothiazines from 2-Alkenyl- and 2-Alkynylanilides and Lawesson Reagent
Reaction of 2-vinylacetanilide with P4S10 gave 2-vinylthioacetanilide, whereas reaction of 2-vinylacetanilide with Lawesson reagent (LR) afforded 2,4-dimethyl-4H-3,1-benzothiazine in 62% yield. Reaction of 2-alkynylanilides with LR gave 4-exomethylene-4H-3,1-benzothiazines in good yields.
Chemoselective Oxypalladation of (o‐Alkynylaryl)amide‐Triggered Site‐Selective C−H Annulation for Stereoselective Synthesis of Succinimide‐Fused Polycycles
We report herein a palladium‐catalyzed, site‐selective cyclative annulation of o‐alkynyl arylamides with maleimide for the stereoselective construction of succinimide‐fused benzoxazine derivatives. This operationally simple and modular protocol provides access to polycyclic frameworks. The other associated features are high functional group compatibility, gram‐scale synthetic potential, and downstream transformations. Control and labeling experiments were conducted to get insights into the mechanism.