1489-57-2Relevant articles and documents
Moss,Ho
, p. 3397,3398 (1976)
(Guanidine)copper Complex-Catalyzed Enantioselective Dynamic Kinetic Allylic Alkynylation under Biphasic Condition
Cui, Xi-Yang,Ge, Yicen,Tan, Siu Min,Jiang, Huan,Tan, Davin,Lu, Yunpeng,Lee, Richmond,Tan, Choon-Hong
supporting information, p. 8448 - 8455 (2018/06/22)
Highly enantioselective allylic alkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminal alkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this transformation. Cold-spray ionization mass spectrometry (CSI-MS) and X-ray crystallography were used to identify some catalytic intermediates, which include guanidinium cuprate ion pairs and a copper-alkynide complex. A linear correlation between the enantiopurity of the catalyst and reaction product indicates the presence of a copper complex bearing a single guanidine ligand at the enantio-determining step. Further experimental and computational studies supported that the alkynylation of allylic bromide underwent an anti-SN2′ pathway catalyzed by nucleophilic cuprate species. Moreover, metal-assisted racemization of allylic bromide allowed the reaction to proceed in a dynamic kinetic fashion to afford the major enantiomer in high yield.
Reaction of cyclic allylic acetates with aliphatic alcohols in the presence of cerium(III) chloride
Uzarewicz,Dresler
, p. 1921 - 1930 (2007/10/03)
The reactions of selected allylic acetates with methanol, ethanol, n-propyl alcohol, isopropyl alcohol and tert-butyl alcohol in the presence of catalytic amounts of cerium(III) chloride are described. Allylic alkyl ethers, bis-allylic ethers and 1,3-dienes were obtained depending on the structure of the acetates.