Regio- and stereoselective 1,6-photocyclization of aspartic acid-derived chiral gamma-ketoamides

Chiral cc-acylamino gamma-ketoamides 2 were irradiated and regioisomeric 1, 6-cyclization products 3 and 4 obtained in high yields. Symmetrically N,N-d isubstituted substrates 2a,b reacted diastereoselectively to give the all-c is products 3a,b in high yields. High 1,3-asymmetric induction was also obs erved for the unsymmetrically N,N-disubstituted 2d and 2e. The stereoselect ivity of these reactions is discussed in terms of SOC-controlled spin inver sion geometries. (C) 1999 Elsevier Science Ltd. All rights reserved.