We report an efficient, one-pot, condition-controlled divergent synthesis strategy through nucleophilic cyclization or Meyer-Schuster rearrangement pathways to construct C-S and C-O bonds for the synthesis of sulfur-containing esters by the opposite reaction conditions (Lewis acid or Brønsted base catalyst). One pathway proceeds with a Brønsted base catalyzed nucleophilic cyclization, affording (Z)-2-benzylidene-2,3-dihydro-5H-benzoe1,4oxathiepin-5-ones in moderate to excellent yields (DBU, PPh3, MeCN, 90 °C, 1 h). Another route involves Lewis acid catalyzed Meyer-Schuster rearrangement to form 3-phenylprop-2-yn-1-yl 2-((3-oxo-3-phenylpropyl)thio)benzoates in moderate to good yields (Fe(OTf)2, Tf2O, PPh3, dioxane, 80 °C, 3 h). The "condition-controlled" strategy offers a novel and selective approach to organic synthesis, significantly enriching the synthetic methodology of sulfur-containing esters.
Shen et al. (Tue,) studied this question.