A nucleophille with pi bond and hydroxyl group,...et al....

[rentsdar34]

I have what i believe are some good questions from a hungry/devoted student: Is only one stereocenter chiral center for a molecule needed to exhibit optical activity?

1. In a nucleophille with both a pi bond and hydroxyl group (e.g. cyclohexene with a propanol chain attached...im embarassed im not sure what the correct name is...) interacting with an electrophille (e.g. Br₂)...my unedrstanding is that one non-bonding lone pair on oxygen is the nucleophile, not the pi bond.. Is this a general rule for nucleophiles with these two fucntional groups/reactive sites? I suppose the lone pair on oxygen has greater electon denisty than the overlapping pi bond and that is why it is -this- orbit which attacts the electrohpile (like Br₂ or something). Will this always happen, assuming similar reactants?

2. Why does higher temp favor eliminations (starts with base attack of beta carbon H+) more than substituion reactions? For example, E₁ competing with SN₁? It would seem the leaving group leaving first in SN₁ would take more energy (higher temperature) to break than the acid base rxn which occurs in E₂? Thank you very much- respectfully- passionate student