Rh(III)-Catalyzed Regio- and Chemoselective [4 + 1]-Annulation of Azoxy Compounds with Diazoesters for the Synthesis of 2<i>H</i>-Indazoles: Roles of the Azoxy Oxygen Atom
作者:Zhen Long、Zhigang Wang、Danni Zhou、Danyang Wan、Jingsong You
DOI:10.1021/acs.orglett.7b00631
日期:2017.6.2
tandem C–H alkylation/intramolecular decarboxylative cyclization of azoxy compounds with diazoesters for the synthesis of 3-acyl-2H-indazoles is disclosed. The azoxy instead of the azo group enables a distinct approach for cyclative capture, leading to a [4 + 1]-annulation rather than a classic [4 + 2] manner. The azoxy oxygen atom is traceless after annulation, and further removal from the product is
or amides can be synthesized in a single step by a carbonylative coupling of α-chloroimines with alcohols or amines under Pd-catalysis. The methodology has been also applied to the preparation of heteroaryl acetic acid derivatives starting from chloromethyl heteroaromatic rings containing a CN double bond. The in situ generation of a β-imino acylpalladium species has been proposed as a key step for
An N-heterocycliccarbenecatalyzedenantioselective [3+3] annulation of benzothiazolyl acetates with 2-bromoenals has been developed. The protocol provides a direct asymmetric synthesis of dihydro-1H-benzothiazolopyridinones in good to very good yields and medium ee values. In many cases, the virtually enantiopure heterocycles are available through a single recrystallization (99% ee).
已经开发了一种 N-杂环卡宾催化的苯并噻唑乙酸酯与 2-溴烯醛的对映选择性 [3+3] 环化。该协议提供了二氢-1H-苯并噻唑并吡啶酮的直接不对称合成,具有良好至非常好的产量和中等 ee 值。在许多情况下,几乎对映纯杂环可通过一次重结晶 (99% ee) 获得。
Stereodivergent Synthesis of Tertiary Fluoride-Tethered Allenes via Copper and Palladium Dual Catalysis
作者:Shao-Qian Yang、Yi-Fan Wang、Wei-Cheng Zhao、Guo-Qiang Lin、Zhi-Tao He
DOI:10.1021/jacs.1c03157
日期:2021.5.19
protocol for the unprecedented stereodivergentsynthesis of tertiary fluoride-tethered allenes bearing a stereogenic center and stereogenic axis via Cu/Pdsynergisticcatalysis. A broad scope of conjugated enynes are coupled with various α-fluoroesters in high yields with high diastereoselectivities and generally >99% ee. In addition, the four stereoisomers of the allene products ensure precise access
Enantioselective Nickel-Catalyzed Michael Additions of Azaarylacetates and Acetamides to Nitroalkenes
作者:Charlene Fallan、Hon Wai Lam
DOI:10.1002/chem.201202093
日期:2012.9.3
Put a nickel in it: Azaarylacetates and acetamides, which have been neglected as substrates in catalytic asymmetric synthesis, undergo highly enantioselective Michael additions to nitroalkenes in the presence of a chiral nickel(II)‐bis(diamine) complex (see scheme; Bn=benzyl, MS=molecular sieves). This process is tolerant of a wide variety of azaarenes in the pronucleophile.