Patent ID: 7718812

Claim:
Process for the preparation of a 2-(6-substituted-1,3-dioxane-4-yl) acetic acid derivative according to formula 1, wherein R 1 , R 2 and R 3 are each independently a C1–4 alkyl group or wherein R 1 and R 2 together with the C-atom to which they are bound form a 5- or 6-membered cycloalkyl and Y stands for R A —CO— or for R B —SO 2 — where R A , R B are chosen from the group of alkyl or aryl with 1–12 C-atoms, from its corresponding 2-(6-substituted-1,3-dioxane-4-yl) acetic acid derivative according to formula 2, wherein R 1 , R 2 and R 3 are as defined above and X stands for a halogen, in the presence of a phase transfer catalyst and an oxylating agent, characterized in that a quarternary phosphonium ion according to formula 3, wherein R 4 , R 5 , R 6 , R 7 each independently stand for an alkyl, cycloalkyl, aralkyl or aryl with 1 to 12 C-atoms, is used as a phase transfer catalyst and an ion according to formula 4, OY − (4) wherein Y is as defined above, is used as an oxylating agent.