7624-24-0Relevant articles and documents
Acyl-carbene and methyl-carbene coupling via migratory insertion in palladium complexes
Meana, Isabel,Albeniz, Ana C.,Espinet, Pablo
, p. 5494 - 5499 (2012/11/07)
The migratory insertion reaction of a carbene into a palladium-acyl bond has been observed both for monoaminocarbenes and for methoxycarbenes. The acyl derivative [PdCl(COMe){C(NEt2)Ph}(PPh3)] undergoes an acyl-carbene coupling, leading to the enolate-type complex [PdCl{C(COMe) (NEt2)Ph}(PPh3)]2 (2). This complex decomposes either by reductive elimination to give the iminium salt or by protonation of the enolate to give a ketoamine. In a similar fashion, the reaction of [Pd 2(μ-Cl)2(COMe)2(SMe2) 2] with [W(CO)5{C(OMe)Ph}] leads to an undetected palladium enolate that, after protonation, is stabilized by coordination to palladium ([PdCl2{(OH)MeC=CPh(OMe}(SMe2)], 8). The reaction of [Pd2(μ-Cl)2Me2(SMe 2)2] with [W(CO)5{C(OMe)-Ph}] leads to the migratory insertion of the carbene into the Pd-methyl group to give an alkyl palladium complex. The transfer of CO from tungsten, followed by insertion into the Pd-Me group, also occurs. This leads to the formation of a Pd-COMe group, which also undergoes migratory insertion of the carbene fragment. These results support that migratory insertion is a key C-C coupling step, as proposed for the new Pd-catalyzed transformations that use carbene precursors.
Novel and efficient insertions of carbons carrying O-, S-, and N-Linked substituents: Synthesis of α-alkoxyalkyl, α-(Alkylthio)alkyl, and α-(Carbazol-9-yl)alkyl ketones
Katritzky, Alan R.,Xie, Linghong,Serdyuk, Larisa
, p. 7564 - 7570 (2007/10/03)
A wide variety of benzotriazolyl-stabilized anions 2, obtained by the lithiation of 1-(α-alkoxyalkyl)-, 1-[α-(alkylthio)alkyl]-, and 1-[α-(carbazol-9-yl)alkyl]benzotriazoles 1, on reaction with aliphatic and aromatic aldehydes and ketones, followed by rearrangement induced by heating in the presence of zinc bromide, furnish one-carbon-homologated α-alkoxyalkyl, α-(alkylthio)alkyl, and α-(carbazol-9-yl)alkyl ketones 4 in simple one-pot operations in good yields with excellent regioselectivity. In several alkoxymethylene insertions, intermediate 2-alkoxyoxiranes were separated in good yields, demonstrating the epoxide mechanism for the rearrangements and providing a facile approach to poly substituted 2-alkoxyoxiranes, another class of important compounds.
A UNIQUE 1,2-SHIFT SELECTIVITY IN 2-HYDROXYPROPIOPHENONE DIMETHYLACETALS: GENERATION OF NEW METHODOLOGIES FOR METHYL-2-ARYLPROPANOATES AND 1,2-CARBONYL TRANSPOSITION
Sonawane, H. R.,Nanjundiah, B. S.,Kulkarni, D. G.,Ahuja, Jaimala R.
, p. 7319 - 7324 (2007/10/02)
α-Hydroxydimethylacetals I have been shown to undergo two different rearrangements involving highly selective 1,2-shifts under mild conditions.When treated with Ph3P/CCl4 in the presence of pyridine, I were cleanly transformed via 1,2-aryl shifts into methyl 2-arylpropanoates, an important class of antiinflammatory agents; a pronounced substituent effect has been observed in this rearrangement. On the other hand, treatment of I with catalytic amount of Ph3P/I2 in benzene furnished α-methoxy-α-aryl propan-2-ones in excellent yields and culminated in the development of a new methodology for 1,2-carbonyl transposition.
