Synthesis of D-ring nogalamine sugar and D-ring sugars of NOG (Scheme 4). The D-ring fragment involved Boc protection and methylation of gentisic acid 30 to afford 31. Directed ortho-lithiation was unsuccessful for arene bromination, perhaps due to tight chelation of the aryllithium to the -OBoc and ester groups. While arylmagnesium bases are not as well-studied for ortho-lithiation, directed magnesiation of 31 with a TMPMgCl•LiCl complex successfully delivered 32 in 52% yield (Scheme 4A). Finally, the nogalose 3 and nogalamine 4 sugars were prepared from modifications to commercially available Lrhamnose and precedented sugar chemistry, respectively (Scheme 4B-C). L-Rhamnose 42 was first converted to the Obenzyl glycoside and protected as the acetonide 33. Oxidation at the C4 position gave ketone 34, enabling the introduction of the C3-methyl substituent by kinetic deprotonation and trapping with MeI to give 35. Acetonide removal and hydride reduction directed by the C3-OH furnished triol 36. Global methylation and benzyl deprotection by catalytic transfer hydrogenation gave 3.