Hello everybody,
I am currently planning a synthetic route and the fourth step is planned as shown below.
I am now suspicious of where the lithiation with LDA (or optionally BuLi) is likely to happen. Literature states that HA is favoured over HB in the similar molecule without a OMe group on the phenyl ring. Does anybody have more knowledge on wheter alpha-lithiation at the HA site or ortho-lithiation at HC, promoted by the direct-metallating group OMe, is favoured?