... Tetrahedron: Asymmetry. ... the best results were obtained with a 1:1.5 ratio of rac-1 and chiral 3 (Table 1, entries 3 and 5). The suitable volume ratio of ... 3 shows a broad band around 3058 and 1028 cm −1 which is compared with the sulfinyl absorption band (1028 cm −1 ) 11 of the ...