1, 3‐Dipolar Cycloadditions of α‐Diazo Ketones Derived from N‐Protected (S)‐Proline with Aromatic and Cycloaliphatic Thioketones. Issue 2 (February 2015)

• Record Type: Journal Article
• Authors: Mlostoń, Grzegorz; Pipiak, Paulina; Linden, Anthony; Heimgartner, Heinz
• Is Part Of: Helvetica chimica acta. Volume 98:Issue 2(2015:Feb.)
• Page Start: 190
• Page End: 200
• Publication Date: 2015-02
• Subjects: Chemistry -- Periodicals; Chemistry, Analytical -- periodicals; Chimie -- Périodiques; 540
• DOI: 10.1002/hlca.201400334
• Languages: English
• ISSNs: 0018-019X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Enantiomerically pure <italic>α</italic>‐oxo diazo compounds derived from (<italic>S</italic>)‐proline were used for 1, 3‐dipolar cycloaddition with aryl and hetaryl thioketones, as well as with cycloalkanethiones. Whereas the reactions with hetaryl thioketones in boiling THF yield <italic>α</italic>, <italic>β</italic>‐unsaturated ketones <italic>via</italic> a cascade of cycloaddition, 1, 3‐dipolar electrocyclization, and desulfurization, the analogous reactions with thiobenzophenone and cycloalkanethiones result in the formation of 1, 3‐oxathiole derivatives. In the latter case, the 1, 5‐dipolar electrocyclization of the intermediate thiocarbonyl ylide is the key step of the reaction sequence. In all cases, the isolated products are optically active, <italic>i.e.</italic>, the multistep processes occur with retention of the stereogenic center incorporated <italic>via</italic> the use of (<italic>S</italic>)‐proline as the precursor of the diazo compounds.</p> </abstract>