Ketone-imide versus ketone-oxime reductive cross-coupling promoted by samarium diiodide: new mechanistic insight gained from a failed aminocyclopentitol synthesis.
[reaction: see text] The intramolecular 1,6-ketone/imide reductive coupling promoted by samarium diiodide competes favorably with an alternative 1,5-ketone/oxime ether coupling in a keto-oxime substrate derived from D-glucosamine N-protected with a phthalimido group. This pinacol coupling reaction affords new homochiral alpha-hydroxylactam scaffolds that could be useful in diversity-oriented synthesis. A mechanistic proposal for this reaction that explains the experimental results is supported by DFT quantum-mechanical calculations on model compounds.
Chiara
Jose Luis
JL
Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain. jl.chiara@iqog.csic.es
García
Angela
A
Cristóbal-Lumbroso
Gabriella
G
D003500:Cyclization; D005944:Glucosamine / Q000737:chemistry*; D005959:Glucosidases / Q000037:antagonists & inhibitors / Q000737:chemistry; D007094:Imides / Q000737:chemistry* / Q000378:metabolism; D007454:Iodides / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry* / Q000378:metabolism; D010091:Oximes / Q000737:chemistry*; D012493:Samarium / Q000737:chemistry*; D013237:Stereoisomerism
D007094:Imides; D007454:Iodides; D007659:Ketones; D010091:Oximes; D012493:Samarium; D005959:Glucosidases; C409809:samarium diiodide; D005944:Glucosamine