Palladium-Catalyzed Cycloisomerization and Aerobic Oxidative Cycloisomerization of Homoallenyl Amides: A Facile and Divergent Approach to 2-Aminofurans
作者:Cungui Cheng、Shuiyou Liu、Gangguo Zhu
DOI:10.1021/acs.orglett.5b00464
日期:2015.3.20
including cycloisomerization and aerobic oxidative cycloisomerization of homoallenyl amides, is described. Varieties of functionalized 2-amino-5-alkylfurans and 2-amino-5-formylfurans can be selectively synthesized in good to excellent yields. Preliminary mechanistic studies show that peroxide may be a key intermediate for this Pd-catalyzed radical aerobic oxidative cycloisomerization of homoallenyl
Et2Zn-promoted β-trans-selective hydroboration of ynamide
作者:Kefeng Wang、Zixi Zhuang、Huihui Ti、Peishan Wu、Xin Zhao、Honggen Wang
DOI:10.1016/j.cclet.2019.11.008
日期:2020.6
Abstract The trans-hydroboration of alkyne represents a challenging task in organic synthesis. Reported herein is an Et2Zn promoted β-trans hydroboration of ynamides by using N-heterocyclic carbene (NHC)-ligated borane as boryl source. The reaction leads to a stereoselective construction of enamides bearing a valuable boryl substituent. Both aromatic and aliphatic ynamides were applicable to the reaction
Zn(II)-Catalyzed One-Pot Synthesis of Coumarins from Ynamides and Salicylaldehydes
作者:Huen Ji Yoo、So Won Youn
DOI:10.1021/acs.orglett.9b01181
日期:2019.5.3
A highly efficient and straightforward synthesis of diversely substituted coumarins from ynamides and salicylaldehydes in the presence of Zn(II) catalyst has been developed. The sulfonamide moiety of ynamides was successfully recycled in this process, serving as an effective traceless directing group for high regioselectivity in the bond-forming event. The advantages of this protocol are good functional
Harnessing the Polarizability of Conjugated Alkynes toward [2 + 2] Cycloaddition, Alkenylation, and Ring Expansion of Indoles
作者:Tapas R. Pradhan、Hong Won Kim、Jin Kyoon Park
DOI:10.1021/acs.orglett.8b02230
日期:2018.9.7
Reported is the utilization of electronically biased conjugated alkynes in the development of highly diastereo- and regioselective dearomative [2 + 2] cycloadditions, alkenylations, and ring expansions of electron-rich indoles. Regioselective protonations of cross- and linear-conjugated alkynes were found to be crucial for accessing various cyclobutene-fused indoline and alkenylated indole derivatives
据报道,在高度非对映和区域选择性脱芳香性[2 + 2]环加成,烯基化和富电子吲哚的环扩展中,利用电子偏置的共轭炔烃。发现交叉和线性共轭炔的区域选择性质子化对于获得各种环丁烯稠合的二氢吲哚和烯基化的吲哚衍生物至关重要。此外,由炔酮成功合成的[2 + 2]酮加合物的容易的环扩展提供了1 H-苯并[ b ]氮杂骨架。
Heterogeneous gold(I)-catalyzed [2 + 2 + 2] annulation between ynamides and nitriles: Straightforward synthesis of tetrasubstituted pyrimidines
作者:Dayi Liu、Quan Nie、Mingzhong Cai
DOI:10.1016/j.tet.2018.05.006
日期:2018.6
heterogeneous gold(I)-catalyzed [2 + 2 + 2] annulation between ynamides and nitriles has been developed that proceeds smoothly under mild conditions and provides a general and powerful tool for the preparation of a variety of tetrasubstituted pyrimidines with high atom-economy, good to excellent yield, and recyclability of the gold(I) catalyst. The reaction is the first example of the heterogeneous gold(I)-catalyzed