CHEM 130 Lecture 8: Sulfur and Phosphorus Compounds

• School: BRCC
• Department: CHEM - Chemistry
• Course: CHEM 130
• Professor: Larry Dalton

Document Summary

Sulfur and phosphorus compounds: nucleophilicity of sulfur compounds. Sulfur analogs of alcohols are called thiols or mercaptans, and ether analogs are called sulfides. The chemical behavior of thiols and sulfides contrasts with that of alcohols and ethers in some important ways. Since hydrogen sulfide (h2s) is a much stronger acid than water (by more than ten million fold), we expect, and find, thiols to be stronger acids than equivalent alcohols and phenols. Thiolate conjugate bases are easily formed, and have proven to be excellent nucleophiles in sn2 reactions of alkyl halides and tosylates. R s( ) na(+) + (ch3)2ch br (ch3)2ch s r + na(+) br( ) Sulfides, for example, react with alkyl halides to give ternary sulfonium salts (equation # 1) in the same manner that 3 -amines are alkylated to quaternary ammonium salts. Although equivalent oxonium salts of ethers are known, they are only prepared under extreme conditions, and are exceptionally reactive.