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

The stability and the stereoselectivity of newly prepared n-pentyl 1-methyl-1H-tetrazol-5-yl (MT) sulfone 1a in the Julia-Kocienski reactions were compared with those of the PT sulfone 1b and the TBT sulfone 1c. The improved stability of the anion derived from the n-pentyl MT sulfone 1a enhanced the efficiency of the olefination reactions and gave higher yields of the product alkenes 3 compared with the PT sulfone 1b. Especially high E-selectivity and high yields were obtained from the reaction with aromatic aldehydes and alpha,beta-unsaturated aldehydes. The selectivity of 1a was not so sensitive to the change of base counter ion compared with the PT sulfone 1b. The reaction of the MT sulfones having either ethyl or a longer alkyl chain also gave E-alkenes selectively in high yields. (C) 2019 Elsevier Ltd. All rights reserved.