Scheme 2.

Coordination of Lewis bases to 2. Reagents and conditions: i) DMAP (1 equiv), −50 °C→RT, DCM, 9, 37 %; ii) 1,3‐Diisopropyl‐4,5‐dimethyl‐imidazol‐2‐ylidene (1.0 equiv), THF 10, 20 %. Molecular structure of compound 9. Anisotropic displacement shown at 50 % probability level. Hydrogen atoms, non‐coordinating triflate anion and solvent omitted for clarity. Selected bond lengths [Å]: C1–S1 1.773(2), C4–S1 1.777(2), S1–N1 1.734(1), S1⋅⋅⋅O1 2.991(1), S1⋅⋅⋅O4 3.821(1), S1⋅⋅⋅O7 2.769(1), S1⋅⋅⋅O8 3.232(1), S2–C20 1.778(2), S2–C27 1.781(1), S2–N3 1.735(1), S2⋅⋅⋅O3 2.986(1), S2⋅⋅⋅O6 2.963(1), S2⋅⋅⋅O8 2.534(1).16