Using the transformation of allyl 2-nitrophenyl thioethers to 3,4-dihydro-2H-1,4-benzothiazines as an example the reductive cyclization of Ï-nitroalkenes to saturated N-heterocycles can be performed highly selective and with high yields if a combination of MoO2Cl2(dmf)2 as a catalyst and Ph3P as reducing agent are employed.
Using Pd/HCOOCs as a surrogate reagentssynthesis of saturated N-heterocycles was described from nitroaromatics as starting materials. The developed new reaction conditions exclude the generally used toxic reagents like carbon monoxide as deoxygenative agent. The developed protocol permits the synthesis privileged bioactive N-heterocyclic scaffolds in good yields and selectivity.