Table 4. Diastereoselective transformations of sulfolanes with construction of quaternary carbon stereocenters ^a .

Entry	Electrophile	Product	Yield (%)	dr	ee (%)
1 b	Selectfluor		92	96 : 4	94
2 b	Selectfluor		89	96 : 4	84
3	NCS		92	97 : 3	93
4	MeI		91	8 : 92	93
5 d	Ethyl acrylate		60	4 : 96	93

^aCompound 2 was treated with 1.2 equiv. of NaH in THF at room temperature, followed by the addition of 1.1 equiv. of electrophile and the subsequent stirring of the reaction mixture for 12 h; isolated yields; the trans : cis diastereomeric ratios were determined by ¹H-NMR; enantiomeric excesses were determined by chiral HPLC.

^bTHF/DMF (2 : 1) used as solvent.

^c[2R,3R] absolute configuration determined by anomalous-dispersion effects in X-ray diffraction measurements on a crystal.

^dThe reaction was stirred for 3 h.