Showing papers by "Lambert Brandsma published in 1986"
59 citations
TL;DR: Norbornene and norbornadiene have been successfully metallated with the complex BuLi · t-BuOK in tetrahydrofuran and a number of derivatives prepared by reaction of the metallic intermediates with electrophilic reagents.
Abstract: Norbornene and norbornadiene have been successfully metallated with the complex BuLi · t-BuOK in tetrahydrofuran and a number of derivatives prepared by reaction of the metallic intermediates with electrophilic reagents.
33 citations
TL;DR: Vinyl potassium was formed directly from ethene by use of a new butyl-lithium-potassium t-butoxide-tetramethylethylenediamine metallating reagent; typical products were obtained with 1bromo-octane and, after addition of LiBr in tetrahydrofuran, with benzaldehyde and diphenyl disulphide as mentioned in this paper.
Abstract: Vinyl potassium was formed directly from ethene by use of a new butyl-lithium–potassium t-butoxide–tetramethylethylenediamine metallating reagent; typical products were obtained with 1-bromo-octane and, after addition of LiBr in tetrahydrofuran, with benzaldehyde and diphenyl disulphide.
28 citations
TL;DR: In this article, the crystal structure of 2,6-bis(lithiumtrimethylsilylmethyl)pyridine · 2TMEDA, which is readily obtained by metallation of 2.6-(Me3SiCH2)2C5H3N, exhibiting double (η3-aza-allyl)-lithiam bonding, represents a beautiful example of C−Li+N−Li +C− charge communication.
24 citations
13 citations
TL;DR: In this article, a mixture of tetrahydrofuran and hexane is used to obtain the dilithio or di-Grignard derivatives by adding anhydrous lithium bromides or magnesium bromide etherate.
Abstract: Phenylacetylene can be dimetallated in two ways. o-K-C6H4-C C - Li is formed by treating phenylacetylene at −70°C with two equivalents of butyllithium and one equivalent of potassium tert-butoxide in a mixture of tetrahydrofuran and hexane. The dimetallation with BuLi-N,N,N′, N′-tetramethylethanediamine (TMEDA) affords a mixture of about 15% (m + p)-Li-C6H4-C C Li and 85% o-Li-C6H4-C C-Li. Ortho-K-C6H4-C C-Li can be transformed into the dilithio or di-Grignard derivatives by addition of anhydrous lithium bromide or magnesium bromide etherate. Reaction of the dilithio derivative with elemental selenium and tellurium, followed by successive addition of tert-butyl alcohol and hexamethylphosphoric triamde (HMPT), gives benzo[b]selenophene and benzo[b]tellurophene in good yields.
Regiospecific functionalization of the nucleus via dimetal derivatives succeeds in the case of alkylation, halogenation, sulfenylation and acylation (with dimethylformamide and dimethylacetamide). Trimethylchlorosilane, chloromethyl methyl ether, aldehydes and ketones do not however react regiospecifically.
TL;DR: Treatment of isoprene with an excess of the couple potassium t-butoxide-lithium tetramethylpiperidide in tetrahydrofuran, followed by addition of a higher alkyl bromide or oxirane, gives the dienes H2CCHC(CH2)CH2R (R) in reasonable yields as discussed by the authors.
Abstract: Treatment of isoprene with an excess of the couple potassium t-butoxide–lithium tetramethylpiperidide in tetrahydrofuran, followed by addition of a higher alkyl bromide or oxirane, gives the dienes H2CCHC(CH2)CH2R (R = alkyl or –CH2CH2OH) in reasonable yields.
TL;DR: Norbornene and norbornadiene have been successfully metallated with the complex BuLi · t-BuOK in tetrahydrofuran and a number of derivatives prepared by reaction of the metallic intermediates with electrophilic reagents as mentioned in this paper.
Abstract: Norbornene and norbornadiene have been successfully metallated with the complex BuLi · t-BuOK in tetrahydrofuran and a number of derivatives prepared by reaction of the metallic intermediates with electrophilic reagents.