Intramolecular carbozincations

Also promising are both intermolecular and intramolecular carbozincation of alkynes catalyzed by №( ) in THF-NMP. The intramolecular cyclic carbozincation has also been observed with -iodo-l-alkenes (Scheme 20). 

Intramolecular carbozincations of alkynes appeared relatively restricted in scope, at least under the conditions that were used to generate the open-chain organozinc species. 

Whereas the interpretation of the NMR parameters of di(5-hexenyl)zinc do not suggest any metal-olefin interaction, probably because the chain length is not appropriate to accommodate the latter in the ground state, this interaction may play a crucial role in the reactive complex leading to the intramolecular carbozincation process. Conversely, the chain length is not sufficiently long in the case of di(4-pentenyl)zinc (28) to achieve the requisite conformation for addition to the double bond, but it is favorable for zinc-olefin interaction24,25. 

Palladium-mediated intramolecular carbozincation preparation of 1 -butyl-1 -(3-nitro-2-phenylpropyl)cyclopentaneZ8... 

Nickel catalysed intramolecular carbozincation preparation of trans-4-(3-carbethoxy-3-butenyl)-4,5-dihydro-(3H)-5-isopropyl-2-furanone31... 

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