Synthesis of thienothiopyranthiones by a new molecular rearrangement.
On heating with alkynes, the readily prepared 1,3-dithioles 3 undergo a new cycloaddition reaction and an unprecedented molecular rearrangement with loss of chlorine to give the first 7H-thieno[2,3-c]thiopyran-7-thiones 4 and 4H-thieno[3,2-c]thiopyran-4-thiones 5 whose structures were confirmed by X-ray diffraction. Unexpectedly, the different alkynes used to form 3 and to convert it into 4 and 5 were incorporated regiospecifically into the thiophene and thiopyran rings, respectively. [reaction: see text]
Ogurtsov
Vladimir A
VA
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, 119991 Moscow, Russia.
Rakitin
Oleg A
OA
Rees
Charles W
CW
Smolentsev
Alexey A
AA
Belyakov
Pavel A
PA
Golovanov
Denis G
DG
Lyssenko
Konstantin A
KA