ABSTRACT
[reaction: see text] A new protocol for the sequential allylic transfer reaction of a diene with two aldehydes in the construction of cyclic systems containing four stereogenic centers is achieved in a one-pot operation. Reaction of the diene-alehyde 1 with aldehyde in the presence of the diboronyl reagent catalyzed by a nickel complex produces products 2 and 3 depending on reaction conditions in high levels of diastereoselectivity. Extension of this method to the synthesis of six-membered rings is also investigated.
ABSTRACT
A highly diastereoselective synthesis of 3 is achieved from the reaction of 1 with hexamethylditin catalyzed by palladium complex in the presence of 20 mol % tris(pentafluorophenyl)borane as a Lewis acid additive for a reversal of diastereoselectivity, whereas 2 is formed in the absence of Lewis acid additive. The method described herein is successful with various substrates 1 in good yields and high levels of diastereoselectivity. [reaction: see text]
