Organocatalysed Asymmetric Direct Mannich Reaction of Acetophenone Derivatives and Dibenzo[b, f][1, 4]oxazepines with Azetidine‐2‐carboxylic Acid. Issue 10 (26th August 2014)

• Record Type: Journal Article
• Authors: Ren, Yuan‐Yuan; Wang, You‐Qing; Liu, Shuang; Pan, Kun
• Is Part Of: ChemCatChem. Volume 6:Issue 10(2014:Oct.)
• Page Start: 2985
• Page End: 2992
• Publication Date: 2014-08-26
• Subjects: Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201402446
• Languages: English
• ISSNs: 1867-3880

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>An enantioselective direct Mannich reaction of different acetophenone derivatives with various substituted seven‐membered cyclic imines using (<italic>S</italic>)‐azetidine‐2‐carboxylic acid as an organocatalyst is described, which provides an efficient access to optically active 11‐substituted‐10, 11‐dihydrodibenzo[<italic>b</italic>, <italic>f</italic>][1, 4]oxazepine derivatives with 87–95 % <italic>ee</italic>. For α, β‐unsaturated ketone benzalacetone, the desired Mannich product was obtained with 72 % <italic>ee</italic>. A plausible transition state is established to explain the observed absolute stereochemistry of the Mannich products. The reaction can also be performed on a gram scale with no adverse effects on the yield and enantioselectivity. Furthermore, some simple transformations involving the Wittig olefination and the decarboxylative reduction of the Mannich products were performed.</p> </abstract>