Preparation of tert-Alkyl Aryl Sulfides from tert-Alcohols via Quinone-mediated Oxidation–Reduction Condensation between tert-Alkyl Diphenylphosphinites and 2-Sulfanyl-1,3-benzothiazole

Abstract

A convenient two-step procedure for the construction of sulfur-containing quaternary centers from tert-alcohols involving chiral ones is established. tert-Alkyl diphenylphosphinites 1 were easily prepared in excellent yields from tert-alcohols and ClPPh2 by the combined use of Et3N and a catalytic amount of DMAP. Subsequent condensation of 1 with thiol 3 smoothly proceeded in the presence of quinone 2d to afford the corresponding tert-alkyl sulfides 4 in good to high yields via SN2 displacement. Removal of benzothiazol-2-yl group of (R)-4j was achieved with LiAlH4 to afford the desired chiral thiol (R)-5 in high yield.

New methods for carbon-nitrogen, carbon-sulfur, and carbon-carbon bond formations by quinone-mediated oxidation-reduction condensation using alkyl diphenylphosphinites

“…Next, carbon-sulfur bond forming reactions between tert-alkyl diphenylphosphinites and 2-sulfanyl-1,3-benzothiazole were investigated. 19) As shown in the previous communication, 20) 2-sulfanyl-1,3-benzothiazole was found to be one of the most reactive sulfurnucleophiles that afforded the corresponding tert-alkyl aryl sulfides in moderate to good yields when the reactions were carried out in the presence of tert-alkyl phosphinites and DMBQ.…”

Recent Advances in Synthesis of Chiral Thioethers

“…In 2005, Mukaiyama et al constructed chiral benzyl thioethers using the Mitsunobu strategy (Scheme 2). [8] In this report, chiral tertiary alcohols (S)-3 were converted to tert-alkyl diphenylphosphinites (S)-5. which were in situ oxidized to its phosphinates by DBBQ. And then substitution with thiol 6 produced chiral benzylic thioethers (R)-7.…”

Synthesis of Chiral Nonracemic Tertiary α-Thio and α-Sulfonyl Acetic Esters via SN2 Reactions of Tertiary Mesylates

“…Mukaiyama reported S N 2 displacement of diphenyl phosphinite derived from α-hydroxy acids in the presence of the appropriate qui-none and benzothiazole9 and Corey reported the displacement of a mesylate derived from the α-hydroxy atrolactic acid 6. With the goal of verifying these procedures with our substrates, we attempted to repeat the known Mitsunobu variant that has been used for the synthesis similar α-thio esters 9. Unfortunately this method did not work well in our hands (Scheme 4).…”