Isobutyl chloroformate

N-Boc-l-phenylalanine, l-phenylalanine methyl ester hydrochloride, d-phenylalanine
methyl ester hydrochloride, and 2-(naphthalen-2-yloxy)acetic acid
were obtained from Sigma-Aldrich; glucono-δ-lactone, 1,4-dioxane,
and lithium hydroxide were purchased from Alfa Aesar; diethyl ether, N-methylmorpholine, sodium hydroxide, and hydrochloric acid
were received from Honeywell; acetonitrile, chloroform, tetrahydrofuran,
and sodium chloride were acquired from Fisher Scientific; hydrogen
chloride (ca 4 mol/L in 1,4-dioxane) was obtained from Tokyo Chemical
Industry; magnesium sulfate, dichloromethane, trifluoroacetic acid,
and isobutyl chloroformate were purchased from VWR International,
Fluorochem, and Thermo Scientific, respectively. All chemicals were
used directly without further treatment. Deionized water was used
throughout this research.
Full synthetic protocols and characterization
data for the two gelators used here are described in the Supporting
Information (Figures S1–S18).

Isobutanol HPLC grade (99% purity) was purchased from Alfa Aesar (Haverhill, MA, USA). The three internal standards (IS) were propionic acid d5 (96% purity), butyric acid d8 (96% purity), and 3-methyl pentanoic acid (>98% purity), and were all purchased from Sigma Aldrich (St. Louis, MO, USA). Additionally, pyridine anhydrous (99.8% purity), isobutyl chloroformate, chloroform HPLC grade (99.8% purity), cyclohexane HPLC grade, and the boiling chip granules of 2–8 mm were purchased from VWR chemicals (Radnor, PA, USA); 99.99% pure sodium hydroxide pellets were purchased from Merck (Burlington, MA, USA). The stock solution of SCFAs at 10 mM was purchased from Sigma Aldrich (St Louis, MO, USA). Mili Q water was produced using a Millipore Milli-Q system with LC-PAK Polisher/Millipak Express 40 and was purchased from Merck Millipore (Burlington, MA, USA).