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A review, with 6 refs., of the prepn. of olefins from phosphonium ylides and carbonyl compds. and from phosphonium ylides, carbonyl compds., org. Li compds., and reactive halogen compds., such as MeCOCH2Cl and EtI. [on SciFinder (R)] ...
Me groups adjacent to an olefinic double bond were metalated by KOCMe3 and BuLi without cis-trans isomerization. Thus, (E)-MeCH:-CHMe was metalated to give (E)-MeCH:CHCH2K (I) which reacted with ethylene oxide to give 41% (E)-MeCH:CH(CH2)3OH. If I was allo ...
Olefins of the formula R1XC:CR2R3 were prepd. by removal of a proton from a betaine-like intermediate, (Ph)3P+-CHR1CR2R3O-, and subsequent treatment with the desired X+. Thus, 1 mole PhLi and the phosphonium salt, (Ph)3PCH2R1.HCl, in 3 parts Et2O and 1 par ...
Reaction of alkenes with N-bromosuccinimide and Et3N.3HF produces vic-bromofluoroalkanes in high yields. As long as the addn. to the C:C bond is sterically unhindered, Br and F get attached with very high regioselectivity, the latter occupying the more sub ...
A review of kinetic control in the diastereogenic formation of C-C bonds, Diels-Alder reactions, [2 + 2] cyclodimerization of olefins, syn preference in the formation of cyclopropanes from olefins and monosubstituted carbenes, reactions of organometallics ...
Under carefully chosen working conditions (solvent, temp.), methyltitanium reagents smoothly convert homoallyl alcs. having a terminal double-bond into (E)-3-penten-1-ols, whereas nonterminal 3-alken-1-ols afford 4-methyl-branched derivs. with configuratio ...
Whereas triphenylphosphonioethanide manifests unsatisfactory cis-selectivities (84.0-95.5%), tris(o,o'-difluorophenyl)- and tri-o-tolylphosphonioethanide react with aliph. or arom. aldehydes and, resp., 2-alkenals or 2-alkynals to afford the olefins with c ...
