Borylative Cyclization of 1,6-Allenynes Driven by BCl<sub>3</sub>
作者:Chun-Hua Yang、Xiangkun Sun、Congcong Niu、Zhiwei Zhang、Mingzhu Liu、Fangjie Zheng、Ling Jiang、Xiangtao Kong、Zhantao Yang
DOI:10.1021/acs.orglett.1c03062
日期:2021.10.15
A metal-free intramolecular borylative cyclization of 1,6-allenynes driven by BCl3 was developed. This method provides a general and practical strategy to construct valuable pyrrolidines containing all-carbon quaternary centers or 3,5-dihydroazepine derivatives depending on the substituents of the allene, with conjugative and sterically hindered phenyl groups favoring the latter.
Alkene <i>versus</i> alkyne reactivity in unactivated 1,6-enynes: regio- and chemoselective radical cyclization with chalcogens under metal- and oxidant-free conditions
作者:Mohana Reddy Mutra、Vishal Suresh Kudale、Jing Li、Wu-Hsun Tsai、Jeh-Jeng Wang
DOI:10.1039/d0gc00321b
日期:——
light-promoted alkene vs. alkyne regio- and chemoselective radical cascade cyclization of electronically unbiased 1,6-enynes with chalcogens to synthesize substituted pyrrolidines bearing chalcogens. The reaction generated three new bonds, namely, C–SO2, C–C, and C–Se under extremely mild conditions. Furthermore, we achieved regio- and chemoselective mono-addition of aromatic thiophenols with unactivated 1,6-enynes
Derivatives of 2-methylenepenam: analogues of clavulanic acid
作者:Edward G. Brain、Nigel J. P. Broom、Roger I. Hickling
DOI:10.1039/p19810000892
日期:——
Some substituted 2-methylenepenams have been synthesised by ring closure of acetylenic azetidinone-thiols. Substituents on the methylene group include aryl, hydroxymethyl, and alkoxycarbonylvinyl.
Regioselective Iron‐Catalysed Cross‐Coupling Reaction of Aryl Propargylic Bromides and Aryl Grignard Reagents
作者:Inés Manjón‐Mata、M. Teresa Quirós、Elena Buñuel、Diego J. Cárdenas
DOI:10.1002/adsc.201901203
日期:2020.1.7
An iron‐catalysed Kumada‐type cross‐coupling reaction between aryl substituted propargylic bromides and arylmagnesium reagents has been developed. Propargylic coupling products were the main or only outcome, and propargyl/allene regioselectivity was shown to depend on the electronic nature of the substituents on the triple bond of the substrate and on the arylmagnesium halide. Best selectivities were
Silver(I)-Catalyzed Tandem Sigamatropic Rearrangement/1,3-H Shift/6π Aza-electrocyclization of <i>N</i>-Propargylic Hydrazones: A Mild Synthetic Route to 1,6-Dihydropyridazines
A highly efficient AgOTf catalyzed [3,3] sigmatropic rearrangement/1,3-H shift/6π aza-electrocyclization cascade reaction of N-propargylic hydrazones has been developed. This method provides a new mild synthetic route to various polysubstituted 1,6-dihydropyridazines including the 3-CF3-substituted ones with high selectivity.