Conjugate addition of lithium (R)-N-allyl-N-(α-methylbenzyl) amide or lithium (R)-N-but-3- enyl-N-(α-methylbenzyl) amide to an alkyl hexa-2, 4-dienoate or alkyl hepta-2, 6-dienoate, followed by ring-closing metathesis of the olefin functionalities within the resultant β-amino ester, generates a range of diastereoisomerically pure azacycles in good yield. These homochiral templates are readily transformed to a range of piperidine alkaloids of the ...