Additions and Corrections: Stereoselective Chemical Reduction of 5,10-Methenyltetrahydrofolate. (Journal of the American Chemical Society (1973) 95(16) (5409–5411)(10.1021/ja00797a050))

The assignment in Figure 1 to the methylene bridge protons of 5,10-methylenetetrahydrofolate is incomplete. The depicted doublet at 4.94 ppm is only one-half of an AX quartet; the remaining half is centered at 3.75 ppm. Instability in the field frequency lock and masking by solvent contributed to the misassignment. The stereochemical preference for one diastereomer in the system illustrated is about 60-70%.