Analogously to Example 21 B) 1)c), a solution of 3.5 ml of (49 mmol) of DMSO in 60 ml of methylene chloride is added at -60° C. to 4.76 g (37.5 mmol) of oxalyl chloride in 33.6 ml of methylene chloride. The addition of 8.94 g (25 mmol) of N-Boc-(p-benzyloxyphenylalaninol) in 150 ml of methylene chloride, 14 ml (100 mmol) of triethylamine in 30 ml of methylene chloride and aqueous working up (extraction of the aqueous phases with ethyl acetate) yields the crystalline title compound: TLC Rf (A)=0.71; 1H-NMR (200 MHz, CDCl3): 1.44 (s, 9 H), 3.06 (d, J=6 Hz, 2 H), 4.39 (m, 1 H), 6.86-6.98 and 7.03-7.15 (2m, each 2 H), 7.30-7.48 (m, 5 H), 9.62 (s, 1 H).
