CHEM 231 Chapter Notes - Chapter 1-10: Protic Solvent, Rate-Determining Step, Steric Effects
4 Apr 2016
School
Department
Course
Professor
Document Summary
Relative stability of created carbocation important 3 tetiary alkyl halides proceed thru sn1 allylic halides and benzylic halides, can also react by an sn1 mechanism because they can form relatively stable carbocations. The rate of sn1 is not affected by concentration or type of nucleophile b/c its not in the rate determining step. Iodide is the largest halide anion and it is the most weakly solvated in a protic solvent; hence, it is the strongest nucleophile among the halide anions. The same effect holds true when we compare sulfur nucleophiles with oxygen nucleophiles. Sulfur atoms are larger than oxygen atoms and hence they are not solvated as strongly in a protic solvent. Thus, thiols (r sh) are stronger nucleophiles than alcohols, and rs anions are better nucleophiles than ro anions. Polarizability of a nucleophile is also important b/c the bigger the electron cloud the better the better the nucleophile bc it can donate more of its charge.
