Patent ID: 8450533

Claim:
A method for the preparation of a compound of the formula comprising the generation of an alcoholate of the formula II and the subsequent cyclopropanation of this alcoholate with a reagent system selected from (A) magnesium metal and dibromomethane, and (B) dibromomethane and a tertiary Grignard reagent, the reaction being carried out in the presence of an ether solvent, C α , C β , C γ and Q being selected according to the possibilities (a) or and (b): (a) C α , C β , C γ represent carbon atoms that may be protonated or substituted with up to a total of 5 substituents for all three carbon atoms, the substituents being selected from the group consisting of alkyl, alkenyl, cycloalkyl and cycloalkenyl groups; and Q represents a moiety selected from (i) a saturated or unsaturated carbon chain having from 1-6 carbon atoms, which carbon atoms are protonated or substituted, the substituents being selected from any of those of C α , C β , C γ ; and (ii) a single covalent bond joining C α and C β ; and; (b) C α , C β , C γ and all or part of Q together form a cycloalkyl or cycloalkenyl ring; and (c) M is an alkali metal, an alkaline earth metal, or an alkaline earth metal monohalide.