Scope of the tandem chain extension-aldol reaction of β-keto imides

CHED 439

Corinne M. Sadlowski, chem.dept@unh.edu and Charles K. Zercher, ckz@christa.unh.edu. Department of Chemistry, University of New Hampshire, Parsons Hall, 23 College Rd., Durham, NH 03824
A zinc carbenoid-mediated chain extension reaction was explored using a β-keto imide in place of the traditional β-keto ester. This allowed for the production of a trans-substituted γ-lactone resulting from a tandem chain extension-aldol reaction, which proceeds with syn-aldol selectivity. The scope of this reaction was investigated by altering the aldehyde. Alternate carbenoid derivatives were also utilized, including 1,1-diiodoethane, and its resulting stereochemistry examined. Attempts are being made to synthesize a chiral bis-imide derivative, which will be subjected to the chain extension-aldol reaction in an effort to control the absolute stereochemistry. A synthetic approach to daunosamine will be described.