▁leaving ▁group ▁can ▁remain ▁in ▁proxim ity ▁to ▁the ▁car b ocation ▁intermediate ▁for ▁a ▁short ▁time ▁and ▁block ▁nucle oph il ic ▁attack . ▁This ▁stands ▁in ▁contrast ▁to ▁the ▁SN 2 ▁mechanism , ▁which ▁is ▁a ▁s tere os pec ific ▁mechanism ▁where ▁s tere och em istry ▁is ▁always ▁invert ed ▁as ▁the ▁nucle oph ile ▁comes ▁in ▁from ▁the ▁rear ▁side ▁of ▁the ▁leaving ▁group . ▁ ▁Side ▁re actions ▁ ▁Two ▁common ▁side ▁re actions ▁are ▁elim ination ▁re actions ▁and ▁car b ocation ▁re arr ang ement . ▁If ▁the ▁reaction ▁is ▁performed ▁under ▁warm ▁or ▁hot ▁conditions ▁( which ▁favor ▁an ▁increase ▁in ▁entropy ), ▁E 1 ▁elim ination ▁is ▁likely ▁to ▁pre dom inate , ▁leading ▁to ▁formation ▁of ▁an ▁alk ene . ▁At ▁lower ▁temper atures , ▁SN 1 ▁and ▁E 1 ▁re actions ▁are ▁compet itive ▁re actions ▁and ▁it ▁becomes ▁difficult ▁to ▁favor ▁one ▁over ▁the ▁other . ▁Even ▁if ▁the ▁reaction ▁is ▁performed ▁cold , ▁some ▁alk ene ▁may ▁be ▁formed . ▁If ▁an ▁attempt ▁is ▁made ▁to ▁perform ▁an ▁SN 1 ▁reaction ▁using ▁a ▁strongly ▁basic ▁nucle oph ile ▁such ▁as ▁hydro x ide ▁or ▁m eth ox ide ▁ion , ▁the ▁alk ene ▁will ▁again ▁be ▁formed , ▁this ▁time ▁via ▁an ▁E 2 ▁elim ination . ▁This ▁will ▁be ▁especially ▁true ▁if ▁the ▁reaction ▁is ▁he ated . ▁Finally , ▁if ▁the ▁car b ocation ▁intermediate ▁can ▁rear range ▁to ▁a ▁more ▁stable ▁car b ocation , ▁it