Dearomatization−Bis-alkylation of Aromatic and Heteroaromatic Diesters Promoted by Me<sub>3</sub>SnLi via a Stanna−Brook Rearrangement
作者:Pablo Monje、Paula Graña、M. Rita Paleo、F. Javier Sardina
DOI:10.1021/ol053130r
日期:2006.3.2
Reaction of Me3SnLi with aromatic and heteroaromatic diesters proceeds through a fast stanna-Brook rearrangement that generates an stable bis-enolate which can be regioselectively alkylated and cyclized, in one step, to bicyclic compounds containing 6,5-, 6,6-, and 6,7-fused ring systems.
作者:Timothy J. Donohoe、Andrew J. McRiner、Peter Sheldrake
DOI:10.1021/ol0065930
日期:2000.11.1
[GRAPHICS]The partial reduction of electron-deficient pyridines is described herein. Mono- and disubstituted pyridines can be transformed into functionalized dihydropyridines using either Birch reduction conditions or sodium/naphthalene in THF. The compounds formed by these high-yielding reductive alkylation protocols have potential as synthetic intermediates, and we have shown that bicycle compounds containing 6,5, 6,6, and 6,7 ring systems can be prepared in one step via a base-promoted cylization.
Use of dissolving metals in the partial reduction of pyridines: formation of 2-alkyl-1,2-dihydropyridines
作者:Timothy J. Donohoe、Andrew J. McRiner、Madeleine Helliwell、Peter Sheldrake
DOI:10.1039/b101662h
日期:——
The partial reduction of a series of electron deficient pyridines to give both 1,2- and 2,5-dihydropyridines is described. The factors that lead to formation of such dihydropyridines are discussed and it was found that, generally, the presence of two activating groups on the pyridine nucleus is optimal. A series of 2-alkyl-1,2-dihydropyridines was prepared using either Birch or sodium naphthalenide reducing conditions and some preliminary derivatisation chemistry has been examined. The identity of three relevant nitrogen containing heterocycles was proven by X-ray crystallography.