Adamantanethione S-methylide (5) is an easily accessible thiocarbonyl S-yli
de. Generated by N-2 elimination from the cycloadduct of adamantanethione a
nd diazomethane, the nucleophilic 1,3-dipole 5 reacts in situ with thiocarb
onyl compounds furnishing 1,3-dithiolanes. 5 and carbon disulfide afford 1:
1 and 2:1 cycloadducts. The structures are assessed by NMR spectra, a X-ray
analysis, and C-S hydrogenolyses. The C=S group is an ambident electrophil
e; the ratios of regioisomeric adducts suggest that electronic effects favo
r the 4',5'-substituted 1,3-dithiolanes, whereas steric effects support the
2',4'-substituted systems. Electrophilic carbonyl compounds and 5 regiospe
cifically provide 2,4-disubstituted 1,3-oxathiolanes. Imines appear to be w
eak dipolarophiles vs. 5. (C) 1999 Elsevier Science Ltd. All rights reserve
d.