10.1021/jo051832o.s003
Akiyuki Hamasaki
Akiyuki
Hamasaki
Richard Ducray
Richard
Ducray
Dale L. Boger
Dale L.
Boger
Two Novel 1,2,4,5-Tetrazines that Participate in Inverse Electron
Demand Diels−Alder Reactions with an Unexpected Regioselectivity
American Chemical Society
2006
reaction conditions
Unexpected Regioselectivity
dienophile choices
Diel
sulfoxides 4
cycloaddition reactions
2006-01-06 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Two_Novel_1_2_4_5_Tetrazines_that_Participate_in_Inverse_Electron_Demand_Diels_Alder_Reactions_with_an_Unexpected_Regioselectivity/3245287
Two new unsymmetrical 1,2,4,5-tetrazines, 3-methylsulfinyl-6-methylthio-1,2,4,5-tetrazine (<b>4</b>) and
3-(benzyloxycarbonyl)amino-6-methylsulfinyl-1,2,4,5-tetrazine (<b>5</b>), were prepared, and the scope of their
participation in intermolecular inverse electron demand Diels−Alder reactions was defined. As anticipated,
sulfoxides <b>4</b> and <b>5</b> (<b>4</b> > <b>5</b>) display a reactivity that is substantially greater than that of their corresponding
sulfides (<b>2</b> and <b>3</b>), being derived from their enhanced electron-deficient character and resulting in a wider
range of potential dienophile choices or the use of milder reaction conditions. The cycloaddition reactions
were expectedly regioselective, typically producing a single cycloadduct, ensuring their synthetic utility,
but both were found to proceed with a regioselectivity opposite what would be anticipated and
complementary to that observed with <b>2</b> and <b>3</b>.