Rhodium(I)-Catalyzed Allenic Carbocyclization Reaction Affording δ- and ε-Lactams
作者:Kay M. Brummond、Thomas O. Painter、Donald A. Probst、Branko Mitasev
DOI:10.1021/ol062842u
日期:2007.1.1
This letter extends the scope of the rhodium(I)-catalyzedallenic 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
Skeletal and appendage diversity as design elements in the synthesis of a discovery library of nonaromatic polycyclic 5-iminooxazolidin-2-ones, hydantoins, and acylureas
Amino-acid derived cross-conjuggated trienes were used as a starting point for the synthesis of a discovery library of over 200 polycyclic 5-iminooxazolidin-2-ones, hydantoins, and acylureas. The main feature of this library synthesis is a triple branching strategy, which provides efficient access to five skeletally diverse scaffolds. In addition, four sets of building blocks were applied in both a front end and a back end diversification strategy. Multiple fused rings were obtained by cyclization of diamides with phosgene and stereoselective Diels-Aider reactions with maleimides. The 5-iminooxazolidin-2-one scaffold was rearranged into the isomeric hydantoin scaffold through a sequence of ring-opening and ring-closing reactions. (C) 2008 Elsevier Ltd. All rights reserved.