4-Amino-2,1,3-benzothiadiazole as a Removable Bidentate Directing Group for the Pd(II)-Catalyzed Arylation/Oxygenation of sp2/sp3 β-C–H Bonds of Carboxamides

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• 作者：Chennakesava Reddy ; Narendra Bisht ; Ramarao Parella ; Srinivasarao Arulananda Babu
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：December 16, 2016
• 年：2016
• 卷：81
• 期：24
• 页码：12143-12168
• 全文大小：1468K
• ISSN：1520-6904

文摘

In this paper, we report 4-amino-2,1,3-benzothiadiazole (ABTD) as a new bidentate directing group for the Pd(II)-catalyzed sp²/sp³ C–H activation/functionalization of various aliphatic/alicyclic/aromatic carboxamide systems. The Pd(II)-catalyzed, ABTD-directed sp³ C–H arylation/acetoxylation of aliphatic- and alicyclic carboxamides afforded the corresponding β-C–H arylated/acetoxylated carboxamides. The Pd(II)-catalyzed, ABTD-directed sp³ C–H arylation of cyclobutanecarboxamide with different aryl iodides afforded the corresponding bis β-C–H arylated cyclobutanecarboxamides having all-cis stereochemistry with a high degree of stereocontrol. The Pd(II)-catalyzed, ABTD-directed arylation/benzylation/acetoxylation/alkoxylation of ortho C(sp²)–H bonds of various benzamides afforded the corresponding ortho C–H arylated/benzylated/oxygenated benzamides. The observed regio- and stereoselectivity in the Pd(II)-catalyzed, ABTD-directed arylation/benzylation of aliphatic/alicyclic carboxamides and benzamides were ascertained from the X-ray structures of representative compounds 5g (bis-β-C(sp³)–H arylated cyclobutanecarboxamide) and 7f (ortho C(sp²)–H arylated benzamide). A brief description on the efficiency, scope, and limitations of bidentate directing group ABTD is reported.