title: Reversal of the importance of steric and electronic effects in the base-promoted α-silylation of sulfides.
abstract: Lithiation of α-C-H groups in organic substrates by RLi or R2NLi followed by silylation with R'3SiCl generally provides analogous products regardless of the R' group of R'3SiCl. A striking exception using 3,4-benzothiophane as substrate depending on whether R' is methyl, phenyl, or isopropyl is demonstrated. With R' = Me or Ph, the geminal α,α-bis-silylated products result whereas with i-Pr3SiCl the trans-α,α'-bis-silylated sulfide is formed. The latter pathway provides ready access to the C2-symmetric enantiomers of trans-2,5-bis(triisopropylsilyl)-3,4-benzothiophane.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Karavadhi
authors.initials: K
authors.lastname: Surendra
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Rajender
authors.initials: R
authors.lastname: Vemula
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
authors.forename: E J
authors.initials: EJ
authors.lastname: Corey