Organocatalytic asymmetric desymmetrization: efficient construction of spirocyclic oxindoles bearing a unique all-carbon quaternary stereogenic center via sulfa-Michael addition
作者:Lu Yao、Kang Liu、Hai-Yan Tao、Guo-Fu Qiu、Xiang Zhou、Chun-Jiang Wang
DOI:10.1039/c3cc42587h
日期:——
An unprecedented enantioselective desymmetrization of spiro cyclohexadienone oxindoles has been developed successfully via organocatalyzed asymmetric SMA, which provides facile access to spirocyclic oxindoles bearing a unique all-carbonquaternary stereogenic center with excellent levels of stereoselectivity.
Iodobenzene-Mediated Intramolecular Oxidative Coupling of Substituted 4-Hydroxyphenyl-N-phenylbenzamides for the Synthesis of Spirooxindoles
作者:Wei Yu、Zhengsen Yu、Xuhui Ju、Junyan Wang
DOI:10.1055/s-0030-1259444
日期:2011.3
effect the intramolecularoxidativecoupling of substituted 4-hydroxyphenyl-N-phenylbenzamides. The transformations could be realized in a catalytic manner by using iodobenzene as catalyst and m-chloroperoxybenzoic acid or urea˙H2O2 as terminal oxidant. This reaction constitutes an efficient method for the synthesis of spirooxindoles. hypervalent iodine - oxidativecoupling - phenolic coupling - spirooxindoles
Discovery and organocatalytic enantioselective construction of axially chiral cyclohexadienylidene skeletons
作者:Shuai Zhu、Jian-Hui Mao、Jun Kee Cheng、Shao-Hua Xiang、Bin Tan
DOI:10.1016/j.chempr.2022.06.014
日期:2022.9
derived by substituting one C=C double bond of allenes with a cyclohexadienyl moiety. Structurally diverse analogs could be accessed in high efficiency with excellent stereocontrol through two facile and direct synthetic strategies, namely CPA-catalyzed asymmetric dearomatization strategy and enantioselective condensation strategy. Notably, the sterically bulky CPA catalyst plays a central role in the extraordinary
spirocyclohexadienone. Mechanistic experiments revealed that the arylhalide was reduced to aryl radical via the single-electron transfer (SET) process under visible light irradiation. The electrophilic addition of an aryl radical with the phenolate anion moiety gave a radical anion intermediate, which recycled the photocatalyst by a second SET process.
本文描述的是由可见光诱导的氧化还原中性分子内脱芳环化。光化学环化由酚盐阴离子衍生的光催化剂催化,并产生螺环己二烯酮。机理实验表明,芳基卤化物在可见光照射下通过单电子转移 (SET) 过程还原为芳基自由基。芳基与酚盐阴离子部分的亲电加成产生自由基阴离子中间体,通过第二个 SET 过程回收光催化剂。
Radical Cyclization Approach to Spirocyclohexadienones
作者:Felix González-López de Turiso、Dennis P. Curran
DOI:10.1021/ol0477226
日期:2005.1.1
Cyclization of an aryl radical at the ipso position of a p-O-aryl-substituted acetamide or benzamide generates oxindoles or quinolones bearing spirocyclohexadienone rings. This versatile reaction is applied to formal syntheses of the vasopressin inhibitor SR121463A and aza-galanthamine.