| Popis: |
The paper describes the preparation of a number of symmetrically substituted 1,3-dienes H2C=C(R)-C(R)=CH2 (3a-d) as well as non-symmetrically substituted 1,3-dienes H2C=C(R1)-C(R)=CR2R3 (3e-i, R ≠ R1) by means of organocuprate induced SN2′ reactions in the esters X-CH2-C≡C-CH2-X (1, X = MeS(O)O or ToS-O) and MeS(O)-O-CH2-C(R1)=C=CR2R3 (4) respectively. An attractive application of the method is the easy preparation of the natural compound myrcene from 4 in which R1, R2 and R3 are hydrogen. A mechanistic rational for the reactions is discussed. |
