Table 2.

Substrate scope of BCPs via intramolecular coupling.

Starting materials and products are racemic mixtures, unless annotated.

^aReaction condition: Cyclobutanone 9 (1.0 equiv., 0.05–1.0 mmol), MesSO₂NHNH₂ (1.2 equiv.) in dioxane (0.1–0.2 M) stirred at rt for 3–12 h, monitored by TLC; then Cs₂CO₃ (3.0 equiv.) was added and stirred at 100 °C for another 3 h.

^b4.8 mmol scale;

^c3.7 mmol scale;

^d18 mmol scale;

^eReaction condition: 1) NaOAc, H₂O₂, 0 °C, 1 h; 2) DMAP, 4-bromobenzoyl chloride, DIPEA;

^f11 mmol scale;

^g30 mmol scale;

^he.e. values were measured after conversion to their alcohol derivatives;

ⁱthe stereochemistry was assigned based on its derivative; TMS, trimethylsilyl; Boc, tert-butyloxycarbonyl; DMAP, 4-dimethylaminopyridine; DIPEA, N,N-diisopropylethylamine; e.e., enantiomeric excess; e.s., enantiospecificity.