10.1021/ol503441d.s001 David M. Hodgson David M. Hodgson Claire L. Mortimer Claire L. Mortimer Jeffrey M. McKenna Jeffrey M. McKenna Amine Protection/α-Activation with the <i>tert</i>-Butoxythiocarbonyl Group: Application to Azetidine Lithiation–Electrophilic Substitution American Chemical Society 2015 adduct electrophile incorporation Application analogue Lithiation thermolysi chiral ligand deprotection Facile Protection lithiation Botc ethanol Boc TFA Azetidine Amine thiocarbonyl alkoxycarbonyl cousin 2015-12-17 06:59:40 Journal contribution https://acs.figshare.com/articles/journal_contribution/Amine_Protection_Activation_with_the_i_tert_i_Butoxythiocarbonyl_Group_Application_to_Azetidine_Lithiation_Electrophilic_Substitution/2047257 <i>tert</i>-Butoxythiocarbonyl (Botc), the long-neglected thiocarbonyl analogue of Boc, facilitates (unlike its alkoxycarbonyl cousin) α-lithiation and electrophile incorporation on <i>N</i>-Botc-azetidine. <i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-<i>endo</i>,<i>endo</i>-Tetramethyl-2,5-diaminonorbornane proved optimal as a chiral ligand, generating adducts with er up to 92:8. Facile deprotection, under conditions that left the corresponding <i>N</i>-Boc systems intact, was achieved using either TFA or via thermolysis in ethanol.