Regioselective allylation and alkylation of electron-deficient alkenes with organogallium and organoindium reagents

Indium in Organic Synthesis

“…Indium-mediated allyl additions to αbenzylidene malonates or similar malonate derivatives were possible with high regioselectivity representing a 1,4-addition. 90,91 Similar results have been obtained with the allylgallium species. 91 However, yields dropped significantly with non-activated double bonds as in norbornen-7-ols.…”

“…90,91 Similar results have been obtained with the allylgallium species. 91 However, yields dropped significantly with non-activated double bonds as in norbornen-7-ols. Acceptable yields of about 72% were obtained only in N-methylpiperidine (NMP) at 180 ºC.…”

Recent applications of gallium and gallium halides as reagents in organic synthesis

“…Research into organogalliums has revealed that these compounds oen display different selectivity from that of conventional Grignard and organolithium reagents. An example of this is the allylgallation of electron-decient alkenes reported by Araki et al 18 They found that triallylgallium reagents may be employed to successfully allylate 1,3-unsaturated nitrile and carbonyl compounds regioselectively affording the 1,4-addition products. The high 1,4-selectivity is not completely understood, though it may be explainable in terms of the soness of these reagents.…”

Recent advances in allylindium reagents in organic synthesis

“…30 The reaction of allylindium sesquihalide with a,b-unsaturated carbonyl compound proceeded in a 1,2-addition mode, whereas, a 1,4-addition took place with triallylindium, as shown in Scheme 30. In addition, 1,4-addition was the major process in the case of a,b-unsaturated nitriles irrespective of the type of allylindium reagent.…”