Nitrile imines four-membered rings

Several of the reactions described in Section 6.16.2.4.6.1 are two-step reactions. After the initial [2+1] addition of the silylene to the multiple bond, a second insertion reaction of a silylene into a reactive Si-X bond of the cyclopropane derivative takes place yielding four-membered ring compounds. Examples are the reactions with alkynes, nitriles, imines, and ketones. 

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