The preparation of 6-bromo-3,4-dihydro-2H-pyrans from tetrahydropyran-2-ones via a Ni(0)-catalysed coupling reaction and their halogen-metal exchange to 6-lithio-3,4-dihydro-2H-pyrans.

摘要

The enol triflate derivatives prepared from readily accessible tetrahydropyran-2-ones undergo Ni(0)-catalysed substitution with LiBr to give the corresponding 6-bromo-3,4-dihydro-2H-pyrans under mild conditions. The 6-bromo-3,4-dihydro-2H-pyrans undergo halogen-metal exchange with tert-butyllithium to give the corresponding 6-lithio-3,4-dihydro-2H-pyrans. [References: 20]