O-17 NMR spectroscopy of sulfolenes (2,5-dihydrothiophene-1,1-dioxides) and sultines (3,6-dihydro-1,2-oxathiin-2-oxides)-experiment and quantum calculations: Synthesis of 4,9-dioxo-1,2-oxathiacyclodecane-2-oxide, a new heterocycle
E. Roversi et al., O-17 NMR spectroscopy of sulfolenes (2,5-dihydrothiophene-1,1-dioxides) and sultines (3,6-dihydro-1,2-oxathiin-2-oxides)-experiment and quantum calculations: Synthesis of 4,9-dioxo-1,2-oxathiacyclodecane-2-oxide, a new heterocycle, CHEM-EUR J, 6(10), 2000, pp. 1858-1864
The products of hetero-Diels-Alder reactions (sultines) and cheletropic add
ition reactions (sulfolenes) between 1,3-dienes and sulfur dioxide can be d
istinguished by their O-17 NMR shifts. Experimental data have been collecte
d for derivatives of 3,6-dihydro-1,2-oxathiin-2-oxide and of 2,5-dihydrothi
ophene-1,1-dioxide. This data was then compared with that calculated by the
gauge independent atomic orbital (GIAO) method at the HF/6-31 + G(d,p) and
HF/6-311 + G(3df, 2p) levels of theory with geometries optimized by MP2/6-
31G(d) calculations. GIAO-MBPT(2) calculations were also performed with the
6-31 + G(d,p) basis set. The adduct between (E)-1-methoxybutadiene and SO2
is sulfolene 3, the ozonolysis of which in SO2 followed by work-up with et
hanol provided (2RS,1SR,6SR)-(31), (2RS,3RS,6SR)-(32), and (2RS,3RS, 6RS)-2
,6-diethoxy-3-methoxy-1,4-oxathiane-4,4-dioxide (33). Single-crystal X-ray
diffraction studies are reported for 32 and 33. Ozonolysis of the hetero-Di
els-Alder adduct of SO2 with 1,3-dimethylidenecyclohexane produced 4,9-diox
o-1,2-oxathiacyclodecane-2-oxide (34), the first member of a new class of s
ulfur heterocycles.