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Compound 104a was prepared, likewise the procedure described for 103b, starting from t-butyl cyclopropanecarboxylate (Kohlrausch, K. W. F. et al. Z Elektrochem. Angew. Phys. Chem, 1937, 43, 282-285) (12.5 g, 88 mmol), 1-bromo-4-chlorobutane (13.7 mL, 117 mmol) and LDA (prepared from BuLi (2.5M in hexanes, 37 mL, 92.5 mmol) and iPr2NH (12.3 mL, 88 mmol, distilled from NaOH)) to give, after purification by fractional distillation under reduced pressure, 104a (10.73 g 52%) as a colorless oil. bp: T=57-61° C. (p=0.001 mbar). 1H NMR: δ 3.52 (t, J=6.6 Hz, 2H), 1.76 (quintet, J=6.8 Hz, 2H), 1.64-1.54 (m, 2H), 1.51-1.46 (m, 2H), 1.42 (s, 9H), 1.12 (dd, J=6.6, 3.9 Hz, 2H), 0.60 (dd, J=6.6, 3.9 Hz, 2H). 13C NMR: δ 173.9, 80.0, 45.1, 33.6, 32.9, 28.2 (3×), 25.3, 24.2, 15.4 (2×). HRMS calcd for C12H22ClO2 (MH+): 233.1308, found: 233.1308.

1. customto give
2. customafter purification
3. distillationby fractional distillation under reduced pressure, 104a (10.73 g 52%) as a colorless oil
4. customT=57-61° C. (p=0.001 mbar)