[Technix540]

Need to know exact mechanism and absolute stereochemistry? This is a beta-gamma unsaturated ketone and we haven't discussed them in class at all. I might be a little tired in the head (exam coming up), but this can't simply be a protonation of the double bond, followed by a nucleophilic attack on the formed carbocation could it? Does anybody have any tips on what type of reaction this is?

[Technix540]

Need to know exact mechanism and absolute stereochemistry? This is a beta-gamma unsaturated ketone and we haven't discussed them in class at all. I might be a little tired in the head (exam coming up), but this can't simply be a protonation of the double bond, followed by a nucleophilic attack on the formed carbocation could it? Does anybody have any tips on what type of reaction this is?

Perhaps the base deprotonates the thiol thus increasing its nucleophilicity. The gamma-position is attacked by the thiol since the delta-position is blocked due to sterics which would arise from the two isopropyl groups. Stereochemistry, since the top face is hindered by the isopropyl group (wedged line) the attack could be made from the bottom face (dashed line)?

[AWK]

5-Isopropyl-2-cyclohex-3-en-1-one is easily isomerized into 5-isopropyl-2-cyclohexen-1-one in both basic and acidic conditions. Michael's addition of thiol will rather proceed with a more stable isomer. The reaction product will be the same and the reaction is unlikely to be stereospecific as both compounds are almost flat.

[Babcock_Hall]

Under basic conditions there is not likely to be a protonation of the double bond.

[Technix540]

5-Isopropyl-2-cyclohex-3-en-1-one is easily isomerized into 5-isopropyl-2-cyclohexen-1-one in both basic and acidic conditions. Michael's addition of thiol will rather proceed with a more stable isomer. The reaction product will be the same and the reaction is unlikely to be stereospecific as both compounds are almost flat.

I see, that makes sense, thank you AWK. My issue is I am not familiar with the isomerization (mechanistic pathway) of the gamma-beta unsaturation to the beta-alfa unsaturation?

[Technix540]

How about this?