1-tert-Butyl-1H-tetrazol-5-yl fluoromethyl sulfone (TBTSO2CH2F): a versatile fluoromethylidene synthon and its use in the synthesis of monofluorinated alkenes via Julia–Kocienski olefination

1-tert-Butyl-1H-tetrazol-5-yl fluoromethyl sulfone (TBTSO2CH2F) has been developed as a new and efficient fluoromethylidene synthon for the synthesis of both terminal and internal monofluoroalkenes via Julia–Kocienski olefination reaction. The base-mediated reaction between TBTSO2CH2F and carbonyl compounds (aldehydes and ketones) provided terminal monofluoroalkenes in good yields with moderate E/Z selectivity. The dominance of E- or Z-fluoroalkenes could be controlled by selection of proper reaction solvent and temperature. TBTSO2CH2F reagent was also found to be readily α-alkylated, acylated, and phenylsulfonylated to give corresponding α-functionalized fluorosulfones, which could be used in the synthesis of alkyl-, acyl-, and phenylsulfonyl-substituted internal monofluoroalkenes via Julia–Kocienski olefination reactions.