J. Org. Chem. 1987, 52, 2977-2979 A sample of 19 was obtained by repeating the reaction for 16 h. Concentration of the organic layer during workup wm carried out at atmospheric pressure and the crude product wm purified by preparative GC: IR (CHC13)1630 ( C 4 )and 2200 cm-' (CN); NMR 2.3-2.8 (m, 4 H), 1.99 (s) on 1.75-2.2 (m, total 5 H). The reaction was repeated for 40 min to obtain a 56:42:02 mixture of 15 (67:33 15a/15b), 18, and 19, respectively. Preparative TLC (CH2Cl2-MeOH,991) of the crude products gave in low yield a fraction enriched in 15b (27:73 15a/15b) as the lower third of the alcohol band IR (film) 3450 (OH) and 2240 cm-' (CN);NMR 6 1.55 (s, 70%) and 1.49 (s,30%)on 1.3-2.9 (m). This enriched material was subjected to refluxing benzene-5% aqueous NaOH for 25 min and at that time the isomer ratio was measured by GC: (67:33 15a/15b). @-Hydroxynitrile 15a (40 mg), benzene (2.5 mL), and aqueous 5% NaOH (2.5 mL) were mixed and stirred at room temperature
2977
for 24 h. Workup as in the above procedure gave 30 mg (75% recovery) of an oil which by GC and NMR was a mixture of diastereomers (6535 15a/15b); no 19 could be detected and only a trace (
