“…In general, N , N -diacyl activation can be accomplished using N -acyclic activating groups − such as C(O)R, where R is an aromatic or heteroaromatic ring ( 3.67 , 3.70 ) or CO 2 R where R is t -Bu group ( 3.78 , 3.80 ); however, more common is the use of cyclic N-activating groups, including heterocycles such as succinimide ( 3.66 , 3.69 , 3.77 ), hydantoin ( 3.68 , 3.71 – 3.72 , 3.74 , 3.76 ), 2,4-thiazolidinedione ( 3.73 ), phthalimide ( 3.75 , 3.91 ), 1,3,5-triazinane-2,4-dione ( 3.79 ), uracil ( 3.81 – 3.83 , 3.85 – 3.87 , 3.89 – 3.90 , 3.94 – 3.96 , 3.99 , 3.101 – 3.103 ), 1,8-naphthalimide ( 3.84 ), thioquinazoline-2,4-dione ( 3.92 ), 1,3,5-triazinane-2,4,6-trione ( 3.93 ), 3-azabicyclo[3.2.1]octane-2,4-dione ( 3.97 ), 1,2,4-triazine-3,5-dione ( 3.98 ), glutarimide ( 3.100 ), and isoquinoline-1,3-dione ( 3.104 ).…”