Carbopalladation simple alkenes

The Pd—C cr-bond can be prepared from simple, unoxidized alkenes and aromatic compounds by the reaction of Pd(II) compounds. The following are typical examples. The first step of the reaction of a simple alkene with Pd(ll) and a nucleophile X or Y to form 19 is called palladation. Depending on the nucleophile, it is called oxypalladation, aminopalladation, carbopalladation, etc. The subsequent elimination of b-hydrogen produces the nucleophilic substitution product 20. The displacement of Pd with another nucleophile (X) affords the nucleophilic addition product 21 (see Chapter 3, Section 2). As an example, the oxypalladation of 4-pentenol with PdXi to afford furan 22 or 23 is shown. 

However, even a--alkylpalladium intermediates formed upon carbopalladation of simple alkenes, which are usually prone to rapid )S-hydride elimination, may serve as relays as demonstrated in the synthesis of bicyclic (Scheme 36, Eq. and tricyclic compounds (Scheme 36, Eq. the latter consisting of three annelated... 

Carbopalladation reactions yield another carbon-bound palladium complex 13, which can undergo a variety of reactions (Scheme 2). The most common pathway yields an alkene 14 via a 5yn-/S-hydride elimination. Two other useful reactions are carbonylation (13- 15) and anion capture (13- 16), which provide opportunities for further function-alization.t Additionally, carbopalladation products can be induced to undergo another carbopalladation reaction, creating the opportunity to forge multiple carbon-carbon bonds. Simple combinations of palladium complex precursors and reactions quickly... 

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