76807-02-8Relevant academic research and scientific papers
Alkylation of Allylic Derivatives. On the Regio- and Stereochemistry of Alkylation of Allylic Alcohols by the Murahashi Method
Goering, Harlan L.,Kantner, Steven S.
, p. 2144 - 2148 (1981)
Direct alkylation of allylic alcohols by the Murahashi method has been reinvestigated.This four-step, one-pot process evidently involves formation of the lithium (allyloxy)alkylcuprate (2) followed by the reaction with (methylphenylamino)triphenylphosphonium iodide (1a) or the corresponding tributylphosphonium iodide (1b).Contrary to earlier implications, the regiospecific and stereospecific anti γ-alkylation is independent of which aminophosphonium reagent is used.Presumably the final step involves alkylation of the (allyloxy)phosphonium ion (3) by LiCu(R)(N(CH3)Ph).This mixed cuprate also alkylates allylic carboxylates with about the same regio- and stereochemistry as for the Murahashi direct alkylation of the corresponding allylic alcohol.A general mechanism is presented that suggests that the regiochemistry of alkylation of allylic derivatives depends on the nature of the ancillary ligand in the alkylating cuprate.
Alkylation of Allylic Derivates. 4. On the Mechanism of Alkylation of Allylic N-Phenylcarbamates with Lithium Dialkylcuprates
Goering, Harlan L.,Kantner, Steven S.,Tseng, Chung Chyi
, p. 715 - 721 (2007/10/02)
Alkylation of allylic N-phenylcarbamates by deprotonation, complexation with CuI in THF, and addition of 1 equiv of RLi results in syn γ-alkylation in both cyclic and acyclic systems.This procedure gives higher stereo- and regiospecificity than when allylic N-phenylcarbamates are reacted with 3 equiv of etheral LiCuR2.A mechanism is presented which incorporates an intramolecular oxidative addition leading to a ?-allyl complex (3) which undergoes reductive elimination to give the syn γ-alkylation product.
