1: 1R,cis 2,2-dimethyl-3-(2-oxo-propyl)-cyclopropane-1-carboxylic acid; PFBHA in water; acetonitrile T=20°C; Condensation; 24 h; 2: BSTFA in hexane; dichloromethane T=60°C; Substitution; 0.666667 h;