A straightforward trifluoromethylation at the C6 position of morphinane alkaloids, their modification and evaluation of inhibition of the SARS-CoV-2 main protease

•A methodology for trifluoromethylation of stereoisomeric 6-ketomorphinans using Ruppert–Prakash reagent.•Selective synthesis of (9α,13α,14α)-8β‑chloro-6,7-didehydro-6-(trifluoromethyl)-3,4,7-trimethoxy-N-methylmorphinane.•(9α,13α,14α)-7,8-Didehydro-1-iodo-6α-(trifluoromethyl)-6β-(hydroxy)-3,4,7-trimethoxy-N-methylmorphinan hor the synthesis of novel 6α-(trifluoromethyl)sinomenin-6β-ol – pyrimidine hybrid compounds.•8β‑chloro-6,7-didehydro-6-(trifluoromethyl)-3,4,7-trimethoxy-N-methylmorphinane shown inhibition of the main viral protease (3CLpro) of SARS-CoV-2.