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
作者:Alan R. Katritzky、Linghong Xie、Larisa Serdyuk
DOI:10.1021/jo960840p
日期:1996.1.1
A wide variety of benzotriazolyl-stabilized anions 2, obtained by the lithiation of 1-(alpha-alkoxyalkyl)-, 1-[alpha-(alkylthio)alkyl]-, and 1-[alpha-(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 alpha-alkoxyalkyl, alpha-(alkylthio)alkyl
Reactions of the Lithium Salts of the Tribenzylidenemethane Dianion, Diphenylacetone Dianion, and Related Compounds
作者:Ortrun Witt、Harald Mauser、Thomas Friedl、Dieter Wilhelm、Timothy Clark
DOI:10.1021/jo971113c
日期:1998.2.1
Potentially synthetically useful reactions of the dilithium salts of the title dianions have been investigated, Electrophilic quenching with a variety of reagents usually leads to the expected products in good yield. Quenching the diphenylacetone dianion with 1 equiv of trimethylchlorosilane, however, gives a good yield of 1,3-diphenylallene obtained by formal elimination of a trimethylsiloxy anion from an intermediate monoquenched monoanion salt. NMR studies, however, do not reveal the intermediacy of the 1,3-diphenyl-2-(trimethylsiloxy)allyl anion but rather suggest that the initial reaction site is at carbon, rather than oxygen, Oxidation of the dianions leads either to ring closure or dimerization for the tribenzylidenemethane dianion and to dimerization for the diphenylacetone dianion. The dimerization reactions are stereospecific, both with respect to the two new stereocenters produced and for the double bonds of the bis-silyl enol ether products if the dimeric bis-enolate dianion products are quenched with trimethylchlorosilane.
A New Use of the Tetrahydrofuran/Powdered Potassium Hydroxide System: Convenient α-Sulfenylation of Ketones and Preparation of Dialkyl Polysulfides
作者:Georges Morel、Evelyne Marchand、André Foucaud
DOI:10.1055/s-1980-29271
日期:——
MOREL G.; MARCHAND E.; FOUCAUD A., SYNTHESIS, 1980, NO 11, 918-921
作者:MOREL G.、 MARCHAND E.、 FOUCAUD A.
DOI:——
日期:——
An activated catalyst RhH(PPh3)4-dppe- Me2S2 for α-methylthiolaton of α-phenyl ketones