Condensation Reactions of a Nitrodienamine with Organocopper and Alkyllithium Reagents Prepared from Pyrrole Derivatives
摘要:
Condensation reactions of a nitrodienamine (1) with Grignard, organocopper and alkyllithium reagents prepared from pyrrole derivatives were investigated.
N-(Triisopropylsilyl)pyrrole. A progenitor "par excellence" of 3-substituted pyrroles
摘要:
A very effective strategy has been devised for the synthesis of 3-substituted pyrroles based on the use of the triisopropylsilyl (TIPS) moiety as a sterically demanding nitrogen substituent to obstruct the attack of electrophilic reagents at the alpha-positions. 1-(Triisopropylsilyl)pyrrole (1) undergoes highly preferential kinetic electrophilic substitution at the beta-position with a variety of electrophiles (Br+, I+, NO2+, RCO+, etc.) and fluoride ion induced desilylation of the products provides the corresponding 3-substituted pyrroles in good overall yields. Competitive trifluoroacetylation experiments demonstrate that substitution of TIPS-pyrrole at the alpha-positions is decelerated by a factor of > 10(4), vs pyrrole at the same sites, without affecting reactivity at the beta-positions. 1-(Triisopropylsilyl)-3-bromopyrrole (2) is readily converted into the 3-lithio compound 44 by bromine-lithium interchange with alkyllithium reagents. This previously unavailable, formal equivalent of 3-lithiopyrrole is itself an excellent source of a wide range of beta-substituted pyrroles, many of which would not be directly preparable from 1. TIPS-pyrrole can be 3,4-dihalogenated and these compounds undergo sequential halogen-metal interchange trapping reactions. This process is exemplified by an efficient, three-step synthesis of the antibiotic verrucarin E (63) from the dibromo compound 5.
Crown-Tetrathiafulvalenes Attached to a Pyrrole or an EDOT Unit: Synthesis, Electropolymerization and Recognition Properties
作者:Gaëlle Trippé、Franck Le Derf、Joël Lyskawa、Miloud Mazari、Jean Roncali、Alain Gorgues、Eric Levillain、Marc Sallé
DOI:10.1002/chem.200400303
日期:2004.12.17
electroactive receptor has been covalently linked to electropolymerizable pyrrole or 3,4-ethylenedioxythiophene monomers. The synthetic route to the monofonctionalized tetrathiafulvalene (TTF) ligand has been optimized. Two derivatives of pyrrole (N- and 3-substituted) were synthesized. The various substituted monomers have been electropolymerized to produce polypyrrole (PP) and poly(ethylenedioxothiophene) (PEDOT)
β-substituted pyrroles via electrophilic substitution of n-triisopropylsilylpyrrole.
作者:Joseph M Muchowski、Dennis R Solas
DOI:10.1016/s0040-4039(00)86011-6
日期:1983.1
N-Triisopropylsilylpyrrole undergoes predominant or exclusive kinetic electrophilic substiution at C-3, and the compounds obtained thereby, upon desilylation with tetra--butylammonium fluoride, give 3-substituted pyrroles in good overall yields.
3-Lithiopyrroles by Halogen-Metal Interchange of 3-Bromo-1-(triissopropylsilyl)pyrroles. Synthesis of Verucarin E and Other 3-Substituted Pyrroles. Preliminary Communication
作者:Joseph M. Muchowski、Reto Naef
DOI:10.1002/hlca.19840670430
日期:1984.6.20
3-Lithio-1-(trimethylsilyl)pyrrole (7, Schem 2), obtained by halogen-metal interchange from the 3-bromo compound 2, reacted with various electrophilic reagents to provide products, which on fluoride ion desilylation, gave 3-substituted pyrroles in good overall yields. One such pyrrole 13 (Schem 3), was converted into 2-formyl-3-octadeclpyrrole (14), reputed to be a metabolite of the marine sponge Oscarella