Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: synthesis of propargyl alcohols and α-ketoesters
作者:Ke Ni、Ling-Guo Meng、Hongjie Ruan、Lei Wang
DOI:10.1039/c9cc04090k
日期:——
The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere.
可见光诱导的溴代炔与醇的偶联反应的化学选择性可以通过对反应气氛进行简单改变来控制。
Intercepting the Banert cascade with nucleophilic fluorine: direct access to α-fluorinated <i>N</i>H-1,2,3-triazoles
作者:J. R. Alexander、P. V. Kevorkian、J. J. Topczewski
DOI:10.1039/d1cc01179k
日期:——
The treatment of propargylic azides with silver(I) fluoride in acetonitrile was found to yield α-fluorinated NH-1,2,3-triazoles via the Banert cascade. The reaction was regioselective and the products result from an initial [3,3] rearrangement. The reaction is demonstrated on >15 examples with yields ranging from 37% to 86%.
The [small alpha]-oxo gold carbenes generated in situ via gold-catalyzed selective oxidation of 4-oxahepta-1,6-diynes were effectively trapped by internal alkynes, resulting in the formation of 2H-pyran-3(6H)-ones 3 and chromen-3(4H)-ones 4 upon...
Transition-metal-catalyzed cross-coupling of propargylic electrophiles and Grignardreagents provides densely functionalized products that are extremely useful synthetic intermediates. However, examples of conversion of propargylic derivatives to form propargyl compounds remain limited due to the challenging regioselectivity. We use LaCl3·2LiCl to catalyze propargylation of Grignardreagents in the absence of
过渡金属催化的炔丙基亲电子试剂和格氏试剂的交叉偶联提供了高度官能化的产物,是极其有用的合成中间体。然而,由于具有挑战性的区域选择性,将炔丙基衍生物转化为炔丙基化合物的例子仍然有限。我们使用LaCl 3 ·2LiCl在没有配体的情况下催化格氏试剂的炔丙基化,具有高区域选择性和立体特异性。该方法显示了使用烷基或(杂)芳基格氏试剂和具有不同离去基团的炔基亲电子试剂的广泛底物范围。我们的方案进一步应用于叶毛多辛 B 的正式合成。利用天然丰富且相对无毒的镧催化剂的方法值得探索。
Rh(III)-Catalyzed Coupling of Benzamides with Propargyl Alcohols via Hydroarylation–Lactonization
作者:Fen Wang、Zisong Qi、Jiaqiong Sun、Xuelin Zhang、Xingwei Li
DOI:10.1021/ol403166p
日期:2013.12.20
Rh(III)-catalyzed C-H activation and annulation of 1-benzoylpyrrolidine with propargyl alcohols has been achieved for an efficient synthesis of (4-benzylidene)isochroman-1-one. Highly enantioenriched products were obtained starting from optically pure propargyl alcohols.