アート錯体 (ate-complex) を用いる高選択的有機合成

抄録

The development of several new procedures for highly selective organic synthesis via organic “ate” complexes including lithium, copper, boron, aluminum, and palladium is described. Dialkenylchloroboranes (1) react with 3 molar equivalents of methylcopper to produce symmetrical (E, E) -1, 3-dienes in high yields. It is revealed that the reaction involves the alkenylcopper-boron complex (loose “ate” complex), free alkenylcopper, and/or copper alkenylborate (tight “ate” complex) as the intermediates. These intermediates further react with allylic halides or alkyl halides to produce stereoselectively E-1, 4-dienes or olefins, respectively. New organocopper reagents, such as RCu·BF₃ and RCu·BR₃, are developed. Complete γ-attack toward allylic halides, direct alkylation of alcohols, and 1, 4-addition to previously unreactive substituted enoate esters and enoic acids are realized by using the former reagent. Stereocontrolled cis-addition to α, β-acetylenic carbonyl derivatives is achieved by using the latter reagent. Regiocontrolled head-to-tail coupling of allylic boron “ate” complexes with allylic halides is accomplished. Complete control to the regiochemistry in the reaction of heteroatom substituted allylic carbanions is realized with the allylic aluminum “ate” complexes which are formed by the addition of triethylaluminum to the carbanions. The stereoselective olefin synthesisvia the reaction of alkenylboranes with palladium acetate is developed.