High-load, oligomeric dichlorotriazine: a versatile ROMP-derived reagent and scavenger.

A new high-load, soluble oligomeric dichlorotriazine (ODCT) reagent derived from ring-opening metathesis polymerization (ROMP) is reported as an effective coupling reagent, scavenger of nucleophilic species, and activator of DMSO for the classic Swern oxidations. Two variants of this reagent (2G)ODCT 4 and (1G)ODCT 16, possessing theoretical loads of 5.3 and 7.3 mmol/g, respectively, have been synthesized. Preparation was accomplished via simple synthetic protocols affording free flowing powders, amenable for large-scale production. Removal of the spent oligomeric reagent was achieved via either precipitation of the spent reagent or simple filtration utilizing a silica SPE, followed by solvent removal, to deliver products in excellent yield and purity. In addition, the corresponding norbornenyl monomer 3 was successfully demonstrated in a couple-ROMP-filter protocol utilizing in situ polymerization, achieving comparable results versus the corresponding oligomeric variant.

Rhodium(I)-catalyzed allenic carbocyclization reaction affording delta- and epsilon-lactams.

This letter extends the scope of the rhodium(I)-catalyzed allenic Alder-ene carbocyclization reaction to the preparation of delta- and epsilon-lactams from amides. A variety of allenic propiolamides were cycloisomerized to give a number of unsaturated delta-lactams. In addition, allenic propargylamides give good yields of the corresponding epsilon-lactams. Formation of lactams possessing these ring sizes has rarely been accomplished via transition-metal-catalyzed carbon-carbon bond forming strategies. Thus, this approach provides an alternative strategy for synthesizing these substructures. [reaction: see text].