1-Methyl-1H-tetrazol-5-yl (MT) sulfones in the Julia-Kocienski olefination: Comparison with the PT and the TBT sulfones

摘要

The stability and the stereoselectivity of newly prepared n-pentyl l-methyl-lH-tetrazol-5-yl (MT) sul-fone la in the Julia-Kocienski reactions were compared with those of the FT sulfone lband the TBT sulfone lc. The improved stability of the anion derived from the n-pentyl MT sulfone la enhanced the efficiency of the olefination reactions and gave higher yields of the product alkenes 3 compared with the PT sulfone lb. Especially high e-seIectivity and high yields were obtained from the reaction with aromatic aldehydes and α,β-unsaturated aldehydes. The selectivity of la was not so sensitive to the change of base counter ion compared with the PT sulfone lb. the reaction of the MT sulfones having either ethyl or a longer alkyl chain also gave e-alkenes selectively in high yields.