Regio- and stereoselective synthesis of cyclobutanes by nickel-catalyzed homodimerizative [2 + 2] cycloaddition using allenamides. (13th April 2021)

• Record Type: Journal Article
• Authors: Kawata, Yuna; Arai, Shigeru; Nakajima, Masaya; Nishida, Atsushi
• Is Part Of: Tetrahedron letters. Volume 69(2021)
• Publication Date: 2021-04-13
• Subjects: Nickel -- Cycloaddition -- Allenamides -- DFT study -- Homodimerization; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2021.152974
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Allenamides are suitable for homodimerizative [2 + 2] cycloaddition under Ni catalysis. Xantphos is an essential and exclusive ligand to promote cycloaddition. Ni(0) with xantphos gives tail to tail selectivity in cycloadducts. DFT calculations revealed the initial oxidative cyclization determines the regio- and stereoselectivity of the products. Abstract: Highly regio- and stereoselective homodimerizative [2 + 2] cycloaddition of allenamides under nickel catalysis was developed. Xantphos is an essential ligand to give " tail to tail " products and DFT studies revealed that oxidative addition between a nickel(0) complex and two distal CC bonds of the allenamides would be a key process. Sequential formation of the metallacycle intermediate would proceed in both a regio- and stereoselective manner to give the corresponding cyclobutane as a single isomer.