Enantioconvergent Cross-Couplings of Racemic Alkylmetal Reagents with Unactivated Secondary Alkyl Electrophiles: Catalytic Asymmetric Negishi α-Alkylations of <i>N</i>-Boc-pyrrolidine
作者:Christopher J. Cordier、Rylan J. Lundgren、Gregory C. Fu
DOI:10.1021/ja4054114
日期:2013.7.31
Although enantioconvergent alkyl-alkyl couplings of racemic electrophiles have been developed, there have been no reports of the corresponding reactions of racemic nucleophiles. Herein we describe Negishicross-couplings of racemic α-zincated N-Boc-pyrrolidine with unactivated secondary halides, thus providing a one-pot, catalytic asymmetric method for the synthesis of a range of 2-alkylpyrrolidines
Formation of RuII-alkyl-butadiene complexes from dihalogeno-RuIV-allyl precursors by the reaction with BrMg(CH2)4MgBr: a novel decomposition pathway for ruthena(IV)cyclopoentane intermediates
Treatment of (C5Me5)RuBr2(η3-CH2C(R)CH2) [R H (1a), Me (1b) with BrMg(CH2)4MgBr in ether afforded the RuII-alkyl-butadiene complexes, (C5Me5)Ru(η4-C4H6)(η1-CH2CHRCH3) [R H (2a), Me (2b)]. Labeling experiments have revealed a mechanism involving a double β-hydrogen elimination from ruthenacyclopentane intermediates and subsequent stepwise transfer of the hydrogen atoms to hydrogenate the η3-allyl
Fixed-charge labels for simplified reaction analysis: 5-hydroxy-1,2,3-triazoles as byproducts of a copper(I)-catalyzed click reaction
作者:Xingqiang Chen、George N. Khairallah、Richard A.J. O’Hair、Spencer J. Williams
DOI:10.1016/j.tetlet.2011.03.094
日期:2011.5
isotope-labelled derivatives of a fixed-charge labelled sugar triazole assisted the identification of 5-hydroxy-1,2,3-triazoles as byproducts of the copper(I)-catalyzed cycloaddition of azides and terminal alkynes. Reaction optimization with inclusion of the auxiliary ligand, tris(benzyltriazolylmethyl)amine furnished an improved ligation protocol in which formation of the 5-hydroxytriazole is mitigated