| Abstract
| - Reaction of (±)-(E)-pent-3-en-2-ol, (±)-(E)-hept-4-en-3-ol, (±)-(E)-2,6-dimethylhept-4-en-3-ol, (±)-cyclohex-2-en-1-ol, and (±)-cyclohept-2-en-1-ol with methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, and benzyl isothiocyanate gave the corresponding racemic O-allylic thiocarbamates of mediumto good thermal stability in good yields. The palladium(0)-catalyzed rearrangement of the (±)-(E)-pent-3-en-2-ol-, (±)-(E)-hept-4-en-3-ol-, (±)-cyclohex-2-en-1-ol-, and (±)-cyclohept-2-en-1-ol-derivedO-allylic thiocarbamates at room temperature in methylene chloride by using Pd2(dba)3·CHCl3 (dba= dibenzylideneacetone) as precatalyst and (+)-(1R,2R)-1,2-bis-N-((2-(diphenylphosphino)benzoyl)-1,2-diaminocyclohexane as ligand for the palladium atom proceeded quantitatively and gave thecorresponding acyclic (R)-configured S-allylic thiocarbamates and the cyclic (S)-configured S-allylicthiocarbamates with ee values ranging from 85% to ≥99% in yields of 76−94%. Rearrangement ofthe O-allylic thiocarbamates carrying a methyl group at the N atom not only was the fastest butalso proceeded with the highest enantioselectivity. No rearrangement was observed under theseconditions in the case of the racemic N-methyl O-allylic thiocarbamate derived from (±)-2,6-dimethylhept-4-en-3-ol, which has a branched carbon skeleton. (S)-Cyclohex-2-enethiol of 97% eewas obtained through hydrolysis of the corresponding N-methyl S-allylic thiocarbamate. 2-((R)-(E)-1-Methylbut-2-enylsulfanyl)pyrimidine of 91% ee and 2-((S)-cyclohex-2-enylsulfanyl)pyrimidineof 97% ee were synthesized in one synthetic operation from the corresponding N-methyl S-allylicthiocarbamates and 2-chloropyrimidine. Similarly, (S)-cyclohex-2-enylsulfanyl)benzene of 97% eewas obtained in one synthetic operation from the corresponding N-methyl S-allylic thiocarbamatethrough a palladium(0)-catalyzed substitution of iodobenzene in the presence of a base. Thepalladium(0)-catalyzed enantioselective rearrangement of O-allylic carbamates to S-allylic carbamates has been extended from the solution phase to the solid phase by using a methylthioisocyanate polystyrene resin. In the case investigated the enantioselectivity of the rearrangementon the solid phase was considerably lower than that in solution.
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