Practical Synthesis of (3aR, 9bR)-8-Fluoro-7-(perfluoropropan-2-yl)-9b-(phenylsulfonyl)-2,3,3a,4,5,9b-hexahydro-1H-benzo[e]indole: An Advanced Intermediate to Access the RORγt Inverse Agonist BMT-362265

A practical and scalable route to (3aR, 9bR)-8-fluoro-7-(perfluoropropan-2-yl)-9b-(phenylsulfonyl)-2,3,3a,4,5,9b-hexahydro-1H-benzo[e]indole 10, an advanced intermediate en route to the synthesis of the RORγt inverse agonist, BMT-362265, is described starting from fluorobenzene. The synthesis involved the screening of multiple synthetic routes for their feasibility and scalability. We also demonstrate the utility of an annulating reagent, (R)-N-(2-chloroethyl)-2-methylpropane-2-sulfinamide, for the diastereoselective synthesis of tricyclic pyrrolidine intermediates 24 and 36 on a multigram scale.