An efficient route to orthogonally protected beta-amino-diacids is described: chiral derivative 3 was shown to be a precursor of enantiopure substituted beta-amino acids. The key step of the procedure is a diastereoselective reduction of beta-enaminolactones 5 by NaBH3CN in CH2Cl2. A study concerning the regio- and diastereoselectivity of alkylation of beta-enarninolactone 3 is also presented. (c) 2005 Elsevier Ltd. All rights reserved.
An efficient route to orthogonally protected beta-amino-diacids is described: chiral derivative 3 was shown to be a precursor of enantiopure substituted beta-amino acids. The key step of the procedure is a diastereoselective reduction of beta-enaminolactones 5 by NaBH3CN in CH2Cl2. A study concerning the regio- and diastereoselectivity of alkylation of beta-enarninolactone 3 is also presented. (c) 2005 Elsevier Ltd. All rights reserved.
Aza-annulation of β-enaminolactones: application to the synthesis of enantiopure difunctionalized bicyclic lactams
Diastereoselective aza-annulation of seven-membered β-enaminolactones 2 gives access to bicyclic heterocyles 5. Fragmentation of molecule 5a with lithium methoxide affords cis or trans bicycliclactams 8 with excellent stereoselectivities.