40648-22-4Relevant academic research and scientific papers
Guanidine–Copper Complex Catalyzed Allylic Borylation for the Enantioconvergent Synthesis of Tertiary Cyclic Allylboronates
Ge, Yicen,Cui, Xi-Yang,Tan, Siu Min,Jiang, Huan,Ren, Jingyun,Lee, Nicholas,Lee, Richmond,Tan, Choon-Hong
, p. 2382 - 2386 (2019/02/01)
An enantioconvergent synthesis of chiral cyclic allylboronates from racemic allylic bromides was achieved by using a guanidine–copper catalyst. The allylboronates were obtained with high γ/α regioselectivities (up to 99:1) and enantioselectivities (up to 99 % ee), and could be further transformed into diverse functionalized allylic compounds without erosion of optical purity. Experimental and DFT mechanistic studies support an SN2′ borylation process catalyzed by a monodentate guanidine–copper(I) complex that proceeds through a special direct enantioconvergent transformation mechanism.
(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
, 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.
Mild two-step process for the transition-metal-free synthesis of carbon-carbon bonds from allylic alcohols/ethers and grignard reagents
Han, Xinping,Zhang, Yanhua,Wu, Jimmy
supporting information; experimental part, p. 4104 - 4106 (2010/05/15)
Chemical Equation Represented A mild two-step process for the regioselective, transition-metal-free preparation of carbon-carbon bonds from allylic alcohols/ethers and Grignard reagents is described. This process obviates the need for the harsh deprotecti
Use of cyclic allylic bromides in the zinc-mediated aqueous Barbier-Grignard reaction
Breton, Gary W.,Shugart, John H.,Hughey, Christine A.,Conrad, Brian P.,Perala, Suzanne M.
, p. 655 - 662 (2007/10/03)
The zinc-mediated aqueous Barbier-Grignard reaction of cyclic allylic bromide substrates with various aldehydes and ketones to afford homoallylic alcohols was investigated. Aromatic aldehydes and ketones afforded adducts in good yields (66-90%) and with good diastereoselectivities. Non-aromatic aldehydes also reacted well under these conditions, but only poor yields were obtained with non-aromatic ketones. Regioselectivity was high when some substituted cyclic allylic bromides were investigated.
Initiated tert-Butyl Hydroperoxide-loaded Low-temperature Autoxidation of Alkenes: Alternative Hydroperoxide Syntheses and the Preparation of a Complete Set of Reference Material
Courtneidge, John L.,Bush, Melanie,Loh, Lay-See
, p. 1539 - 1548 (2007/10/02)
A complete set of characterization data for the allylic hydroperoxides prepared from 1-methylcyclohexene and the isomeric 4-methyloct-4-enes is presented.The data relies upon the preparation of allylic hydroperoxides by tert-butyl hydroperoxide-loaded autoxidations, singlet-ene oxidations and nucleophilic substitution reactions.Appropriate allylic alcohols and relevant scission products have been prepared to support the assignments given.
