. Author manuscript; available in PMC: 2017 Jun 29.

Published in final edited form as: J Am Chem Soc. 2016 Jun 15;138(25):7939–7945. doi: 10.1021/jacs.6b03444

Table 2.

Comparison of peptide's C-terminus cap^a,b

entry	peptide	3a % remaining	4a % conv.	4a er	7a % conv.
1	L10	13	75	91:9	12
2	L13	13	65	86:14	22
3	L6	12	66	89:11	22

Reaction conditions: substrate (0.4 mmol), diethyl malonate (1.1 equiv), Cu(MeCN)₄BF₄ (5 mol%), peptide (10 mol%), Cs₂CO₃ (3.2 equiv), DMF/Tol (0.5/1.1 mL).

Conversions were determined by 1H NMR and enantiomeric ratios were determined by chiral high performance liquid chromatography analysis, see supporting information for details.