Barbier-type allylation of acetals with allyl bromide in a Pb/Al bimetal redox system

“Design” of Boron‐Based Compounds as Pro‐Nucleophiles and Co‐Catalysts for Indium(I)‐Catalyzed Allyl Transfer to Various Csp3‐Type Electrophiles

“…[8] This observation prompted us to investigate the CÀC coupling between 2 a and ethers, another class of Csp 3 -type electrophiles. It was reasoned that these by-products might be formed by further allylation of the initially generated homoallylic ethers.…”

“…It was reasoned that these by-products might be formed by further allylation of the initially generated homoallylic ethers. [8] This observation prompted us to investigate the CÀC coupling between 2 a and ethers, another class of Csp 3 -type electrophiles. However, owing to the relatively strong CÀO bond, allylation of ethers is expected to be significantly more challenging than that of acetals and ketals.…”

“…While surveying the scope for the InOTf‐catalyzed allylation of acetals and ketals with allyl boronate 2 a , we detected for certain substrates the formation of diallylated products in trace amounts. It was reasoned that these by‐products might be formed by further allylation of the initially generated homoallylic ethers 8. This observation prompted us to investigate the CC coupling between 2 a and ethers, another class of Csp 3 ‐type electrophiles.…”

Synthesis of a stable indium complex derived from γ-silyl-α,α-difluorobromopropyne: evaluation of experimental parameters

“…In all cases studied, a discrete organometallic intermediate, such as the one found with indium (i.e., 2a), was not observed by 19 F NMR; and none of the reactions conditions produced the desired allenol 5a. The use of cadmium [9,10] gave rise to the homopropargyl alcohol 4a (entry 1); when lead was used [11,12], the only compound observed was the reduced product TIPS-CC-CF 2 H (6a) (entry 2). Under a variety of reaction conditions, gallium-which has a similar first ionization potential and reduction potential as indium, [13] only furnished dimer 3a.…”

Trimethylsilyl Trifluoromethanesulfonate Catalyzed One-Pot Method for the Conversion of Aldehydes to Homoallyl Ethers in an Ionic Liquid

“…The allylation of acetals using organosilicon reagents is a useful method to generate homoallyl ethers and several catalysts have been used to effect this transformation. These include titanium(IV) chloride, 3 aluminum trichloride, 4 boron trifluoride-diethyl ether complex, 4 trityl perchlorate, 5 diphenylboryl trifluoromethanesulfonate, 5 montmorillonite, 6 lead/aluminum, 7 trimethylsilyl bis(fluorosulfo-nyl)imide, 8 iodotrimethylsilane, 9 trimethylsilyl trifluoromethanesulfonate (TMSOTf), 10 dicyclopentadienylbis(triflyloxy)titanium(IV) [Ti(Cp) 2 (CF 3 SO 3 ) 2 ], 11 trifluoroacetic acid, 12 bismuth tribromide, 13 trimethylsilyl bis(trifluoromethanesulfonyl)amide (TMSNTf 2 ), 14 scandium(III) trifluoromethanesulfonate, 15 indium metal, 16 and bismuth(III) trifluoromethanesulfonate. 17 One drawback of using acetals for the synthesis of homoallyl ethers is that they often have poor shelf lives or are not commercially available and need to be synthesized from the corresponding aldehyde.…”