Comparison of the partition between polar and SET pathways in the SRN1 mechanism for the nitronate and diethyldithiocarbamate anions. An unexpected result

Abstract Competition between S RN 1 and S N 2 mechanisms is discussed according to the stereochemical results in the alkylation of two anions by optically active α -chloro para nitrophenylethane 1 . In the reaction of 1 with the ambident anion of 2-nitropropane 2 , competing S RN 1 and S N 2 processes take place, giving C-alkylation 3 with complete racemization and O-alkylation 4 products respectively. On the other hand, S-alkylation of the diethyldithiocarbamate anion 5 by the halide 1 involves also an S RN 1-S N 2 competition giving the same product 6 with an indication of a less important participation of the S RN 1 pathway despite the fact that dithiocarbamate is a better reducing agent than nitronate.