Trans-Selective Olefination of Carbonyl Compounds by Low-Valent Titanium-Mediated Dehydroxybenzotriazolylation

• Published in: Journal of organic chemistry Vol. 63; no. 19; pp. 6704 - 6709
• Main Authors: Katritzky, Alan R, Cheng, Dai, Henderson, Scott A, Li, Jianqing
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 18.09.1998; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; KETONES; ROUTE; REAGENTS; LITHIO DERIVATIVES; STEREOCHEMISTRY; CHEMISTRY; SULFONES; BENZOTRIAZOLE
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo980616v

Lithiation with n-butyllithium of a variety of benzotriazole derivatives 1a − f and 5a − d, all containing a proton α to the benzotriazolyl moiety, gave anions which underwent addition to aliphatic, aromatic, and α,β-unsaturated aldehydes and cyclic and acyclic ketones. The resultant N-(β-hydroxyalkyl)benzotriazole derivatives 3a − m, 6a − g, 9a − d, and 10a were dehydroxybenzotriazolylated when treated with low-valent titanium to give alkenes 4a − m, dienes 7a − j, and triene 11a, with selectivity for the trans isomers without separation of diastereoisomeric intermediates. This method offers an alternative to the three most frequently used methods for the formation of alkenes from carbonyl compoundsthe Wittig, Peterson, and Julia reactionsespecially in the formation of tri- and tetrasubstituted alkenes.