Inversion of the absolute configuration on the stereogenic center of enantiomerically pure chlorohydrin (R)-(+)-4via direct Mitsunobu esterification of (R)-(+)-4 (Method A–B) or indirect acetolysis of the respective mesylate (R)-(+)-9 (Method C–D).

Entry	Substrate	Methoda	Conv.b [%]	Yieldc [%]	eepd [%]
1	(R)-(+)-4 (>99% ee)	A	>99	44	18
2		B	N.D.e	6	81
3	(R)-(+)-9 (>99% ee)	C	70	18	98
4		D	92	34 (36)f	98 (>99)f

^aMethod A: (R)-(+)-4 (100 mg, 0.42 mmol, >99% ee), 4-nitrobenzoic acid (1.5 equiv.), DEAD (1.5 equiv.), Ph₃P (1.5 equiv.), dry THF, 12 h, 25 °C; Method B: (R)-(+)-4 (239 mg, 1.00 mmol, >99% ee), 2,4-dinitrobenzoic acid (1 equiv.), (2-hydroxybenzyl)diphenylphosphine oxide (cat.), xylene, reflux with a Dean–Stark trap for 48 h; method C: (R)-(+)-9 (50 mg, 0.16 mmol, >99% ee), AcOCs (5.0 equiv.), 18-crown-6 (cat.), dry PhCH₃, 120 h, 90 °C; method D: (R)-(+)-9 (50 mg, 0.16 mmol, >99% ee), AcOCs (5.0 equiv.), 18-crown-6 (cat.), dry PhCH₃, 120 h, 110 °C.

^bDetermined by GC analysis using the calibration curve.

^cIsolated yield after silica-gel column chromatography.

^dEnantiomeric excess of optically active compounds, i.e., (S)-10, (S)-11, and (S)-(+)-5a, determined by HPLC analysis.

^eNot determined.

^fPerformed on 500 mg (1.57 mmol) scale of (R)-(+)-9.