STEREOSPECIFIC SYNTHESIS AND ABSOLUTE-CONFIGURATION OF OPTICALLY-ACTIVE DIARYL(ACYLOXY)(ALKOXY)SPIRO-LAMBDA(4)-SULFANES

Optically active (R)-(+)-1,1'-spirobi[3H-2, 1-benzoxathiol]-3-one (R)- (+)-5, the (R)-(+) and (S)-(-) enantiomers of thiol-1,1'-naphtho[1,8-d ,e]-3H-2,1-oxathiin-3-one] (R)-(+)-8 and S-(-)-8, and hiol-3-one-1,1'- naphtho[1,8-d,e]-3H-2,1-oxathiine] (S)-(+)-10 all belonging to the cla ss of diaryl(acyloxy)-(alkoxy)spiro-lambda(4)-sulfanes (spirosulfurane s) were prepared by dehydration of the optically active diaryl sulfoxi des (R)-(+)-4, (R)-(-)-7, (S)-(+)-7, and (S)-(+)-9, respectively, all of them carrying reactive CH2OH and COOH substituents. (R)-(+)-5H,7H-d ibenzo[c,f]-1,5-oxathiocin-5-one 12-oxide (R)-(+)-6, a sulfoxide-lacto ne isomer of spiro-lambda(4)-sulfane (R)-(+)-5 was also obtained from (R)-(+)-4 by dehydration. The molecular structures including the absol ute configurations were determined for (R)-(+)-5, (R)-(+)-6 and (R)-()-8 by X-ray diffraction method. Relevant bond length and angle data a re listed. Sulfur configurations, solid-state conformations and a ster eospecific pathway for the dehydration of sulfoxides are discussed in detail. (C) 1997 Elsevier Science Ltd.