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High chelation control of three contiguous stereogenic centers in the Reformatsky reactions of indium enolates with alpha-hydroxy ketones: unexpected stereochemistry of lactone formation.

Research paper by Srinivasarao Arulananda SA Babu, Makoto M Yasuda, Yuji Y Okabe, Ikuya I Shibata, Akio A Baba

Indexed on: 30 Jun '06Published on: 30 Jun '06Published in: Organic Letters



Abstract

[reaction: see text] A boat-type of chelated bicyclic transition state involving highly diastereoselective construction of three contiguous stereogenic centers in the Reformatsky reaction of indium enolates with alpha-alkoxy/hydroxy ketones is proposed. alpha-Hydroxy ketones with indium enolates furnished highly diastereoselective lactones, while alpha-alkoxy ketones gave acyclic esters in moderate selectivities. X-ray structure analyses of key products unequivocally revealed the unexpected stereochemistry of products and the reaction pathway.