2-Bromo-5-methylthiophene → 4-[1-(3-Bromo-5-methyl-thiophen-2-yl)-methanoyl]-piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

Prepared essentially as in 29a except that 2-bromo-5-methyl thiophene is used as the starting material. In addition, 1.20 equivalents of lithium diisopropylamide and 1.24 equivalents of 4-(methoxy-methyl-carbamoyl)-piperidine-1-carboxylic acid. tert-butyl ester are used for the reaction. Accordingly, stirring time of the reaction mixture may vary. Purification of the residue via flash column chromatography uses a gradient with a mixture of ethyl acetate: n-heptane (1:9) to ethyl acetate: n-heptane (2:8) to yield a yellow oil. LC/MS (ESI), m/e 332 (M-56) and 388 (MH+), retention time 2.15 minutes. Condition II.

Provenance & Evidence