2- Cyclohexyl-2-pyrroline

In addition to a-additions to isocyanides, copper oxide-cyclohexyl isocyanide mixtures are catalysts for other reactions including olefin dimerization and oligomerization 121, 125, 126). They also catalyze pyrroline and oxazoline formation from isocyanides with a protonic a-hydrogen (e.g., PhCH2NC or EtOCOCHjNC) and olefins or ketones 130), and the formation of cyclopropanes from olefins and substituted chloromethanes 131). The same catalyst systems also catalyze Michael addition reactions 119a). 

Taking advantage of an intramolecular Wittig reaction, the a-amidoketones 316 underwent annulation to the 3-pyrrolines 317 upon treatment with the ylide 318 <199581151>. These intermediates could be further elaborated to the pyrroles 319 by base-induced elimination of benzenesulfinic acid (Scheme 37) <2000TL8969>. It should also be mentioned that a set of unusual 3-pyrroline-2-ones have been synthesized by Ugi s four-component reactions from phenacylamine hydrochloride, cyanoacetic acid, cyclohexyl isocyanide, and aldehydes, involving final formation of the C(3)-C(4) bond <1999H(50)463>. 

Nitro-l-cyclohexyl-3-ethoxy-2-oxo-3-pyrroline and acetonitrile added to a soln. of L-leucine in borate buffer soln. of pH 10.0, and the resulting suspension stirred 1 hr. at room temp. N-(4-nitro-l-cyclohexyl-2-oxo-3-pyrrolin-3-yl)-L-leucine. Y 93%.. - The protective group can be removed at room temp, by NHg in acetonitrile. F. e. s. P. L. Southwick, R. F. Dufresne, and J. J. Lindsey, J. Org. Chem. 39, 3351 (1974). 

A novel three-component reaction sequence leading to 5-hydroxy-3-pyrrolin-2-ones has been reported by Liang and coworkers (Scheme 108 2007T8987). Mixing arylaldehyde 410, 2,4-pentanedione (361), and cyclohexyl isocyanide (260) with piperidine gives the 3-pyrrolin-2-one 411. The reaction proceeds via the formation of2-aminofuran intermediates followed by a Dimroth-type rearrangement to the corresponding 3-pyrrolin-2-ones. 

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