Preparation of homoallylic compounds by reaction of cyclopropylvinyl precursors with bronstedt acids

1. A method of forming homoallylic compounds 2 from cyclopropylvinyl precursors 1 in the presence of a Bronsted acid HQ

wherein, the Bronsted acid HQ is selected from R′CO 2 H and/or a hydrogen halide selected from HCl, HBr or HI, wherein R is a C 1-30 cyclic, polycyclic or acyclic alkyl residue, or an aryl or polyaryl residue, each of which may be saturated or unsaturated, branched or linear, and substituted or unsubstituted; R′ is a C 1-30 alkyl or aryl residue, which may be linear or branched and may be substituted or unsubstituted, and wherein Q is R′CO 2 and/or a halide atom.

2. The method of forming a homoallylic alcohol according to claim 1

by hydrolysis of rearrangement product 2.

3. The method of forming a homoallylic alcohol according to claim 2 , wherein the E/Z ratio is greater than 70:30.

4. The method according to claim 1 , wherein the residue R contains carbon-carbon unsaturation.

5. The method according to claim 1 , wherein the precursor 1 is a polyprenoid

wherein n is 1, 2 or 3.

6. The method according to claim 5 wherein the precursor 1 is a cyclopropanated farnesene.

7. A method of forming the compound:

comprising the step of forming E,E-homofarnesol in accordance with the method defined in claim 1 , and cyclizing the E,E-homofarnesol so formed using the bacterial enzyme squalene hopene cyclase.

8. The method of forming a homoallylic alcohol according to claim 3 , wherein the E/Z ratio is greater than 75:25.

9. The method of forming a homoallylic alcohol according to claim 3 , wherein the E/Z ratio is greater than 80:20.

10. The method of forming a homoallylic alcohol according to claim 1

by transesterification and/or nucleophilic substitution of rearrangement product 2′ to esters of the general structure 2, said esters being hydrolyzed with aqueous base to homoallylic alcohols of the general structure 3.