Gallium-mediated allyl transfer from bulky homoallyl alcohol to aldehydes or alkynes: Control of dynamic σ-allylgalliums based on retro-allylation reaction
reagent and gallium trichloride, bulky homoallylalcohols undergo gallium-mediated retro-allylation reaction to provide σ-allylgallium reagents. The σ-allylgallium reagents generated were applied to carbonyl allylation. The retro-allylation reaction generates (Z)- and (E)-σ-crotylgalliums stereospecifically, starting from erythro- and threo-homoallyl alcohols, respectively. The stereochemically defined
Under catalysis of Pd(OAc)2-(P-n-Bu)3, Et2Zn promotes a variety of allyl alcohols to undergo nucleophilic allylation of aliphatic aldehydes and ketones at room temperature and provides homoallyl alcohols in 60–90 and ca. 60% isolated yield, respectively. The reaction is irreversible and kinetically controlled, and unique regio- and stereoselectivities observed for the allylation with unsymmetrically