Aminocyclopropanes, cycloaddition

Formation of aminocyclopropanes in a carbene cycloaddition to a carbon-carbon double bond containing no nitrogen function requires an amino-substituted carbene as counterpart. Such a type of reaction was observed with special nitrile ylides possessing a suitable double bond within the molecule Thus, nitrile ylides (193) generated from the precursors 191 or 192, underwent intramolecular [2-f-l] or [2-I-3]cycloaddition yielding 194 and 195 respectively (Scheme 4). 195 was easily hydrolyzed to aminocyclo-propane (196). The preferential direction of the cycloaddition was influenced by the nature... 

A special aminocyclopropane (409) could be prepared by cycloaddition of azide (406) with compound 407 (equation 101) (see also Section II.A.2.b for an easy preparation of cyclopropyl azides see Ref. 218). 

Cycloaddition of nitrone (415b) to the imino function in 414 gave aminocyclopropanes 417 or 418 as well as other products (equation 103). The expected, primary product, 416, was obtained from a nitrile ylide (415a) by a cycloaddition reaction. ... 

Cycloaddition. Species derived from oxidative opening of aminocyclopropane derivatives by CAN can be intercepted by a remote double bond, leading to cyclopentanes. The following example shows N-debenzylation during the process. 

Waser and coworkers have reported the first use of amino cyclopropanes in [3+2]-cycloadditions with aldehydes to give amino tetrahydrofurans with high levels of diastereoselectivity (Scheme 22) [22]. A wide range of activators could be used in these reactions including normally inert Lewis acids like FeCL on AI2O3. In contrast to the Johnson et al. work mentioned above, racemic tetrahydrofurans resulted from the use of enantiomerically eiuiched aminocyclopropanes implying that the reaction proceeds through a zwitterionic intermediate. 

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