Allyl deprotection to liberate free hydroxy, amino and acid groups from the corresponding allylethers, amines and esters is achieved under mild conditions. The reagent combination employed for this transformation is polymethylhydrosiloxane (PMHS), ZnCl2 and Pd(PPh3)4.
Pyrolysis of allyl ethers. Unimolecular fragmentation to propenes and carbonyl compounds
作者:R. C. Cookson、S. R. Wallis
DOI:10.1039/j29660001245
日期:——
about 500° allylethers undergo decomposition through a cyclic, six-atom transition state with transfer of a hydrogen atom to give high yields of a carbonylcompound and a propene, in which the double bond has moved from the 2,3- to the 1,2-position of the allyl system. The rate of reaction is rather insensitive to structural variation in either the allyl or alkyl part of the ether. Allyl α-deuterodiphenylmethyl
Protecting group-free use of alcohols as carbon electrophiles in atom efficient aluminium triflate-catalysed dehydrative nucleophilic displacement reactions
作者:Adam Cullen、Alfred J. Muller、D. Bradley G. Williams
DOI:10.1039/c7ra08784e
日期:——
Benzylic and allylic alcohols are rendered electrophilic without chemical modification by the use of aluminium triflate as catalyst. The reaction succeeds with alcohol, thiol, carbon and nitrogen nucleophiles. When phenols are employed as nucleophiles, C-alkylation ensues. An advanced application of the method is demonstrated in the synthesis of 2H-chromenes and their N and S analogues.
Practical preparation of diphenylmethyl ethers from 2-diphenylmethoxypyridine using catalytic iron(<scp>iii</scp>) chloride
作者:Van Hieu Tran、Minh Thanh La、Hee-Kwon Kim
DOI:10.1039/c9ob01093a
日期:——
e was developed. A variety of DPM ethers was successfully achieved with high yield via treatment of alcohols with 2-diphenylmethoxypyridine in the presence of catalytic FeCl3. The procedure is a practical and efficient synthetic procedure to protect various alcohols, and it can be applied to prepare bioactive compounds.