合成这些 de [dimethyl-5,5 dioxannylidene-2]-3 cyclopentanecarboxylate demethyle a partir dedimethyl-6,6 methylene-1 dioxa-4,8 spiro [2.5] 辛烷和 de crotonate demethyle。Le crotonate demethyle peut etre 替换 par d'autres 酯(例如庚烯-2oate demethyle)或内酯(例如二氢呋喃酮-2)。在 obtient dans ce dernier cas des 上推导 de cyclopenta [c] furannone
Thermal hetero [3 + 2] cycloaddition reaction of a dipolar trimethylenemethane 2 with an N-acyl or N-tosyl imine gives an α-methylene-γ-pyrrolidone acetal 4 in high yield, which upon hydrolysis affords a γ-amino acid derivative.
Dipolar trimethylenemethane species, thermally generated from 2,2-dialkoxy-1-methylenecyclopropane, reacts with a dialkylzinc reagent to generate an allylic zinc reagent, which then reacts in situ with a carbonyl compound to give a hydroxy acetal product as the result of coupling of the three reactants.
Synthesis and [2 + 2] Cycloaddition of Dimethyleneketene Acetals. Reaction with C60 and Facile Hydrolysis of the C-C Bond Connected to C60
作者:Shigeru Yamago、Atsuo Takeichi、Eiichi Nakamura
DOI:10.1021/ja00082a041
日期:1994.2
We report here that the O-alkylated enolates of cyclopropanecarboxylates (dimethyleneketene acetals 3) can be prepared from readily available precursors, and that they are extemely reactive, serving as useful surrogates of the elusive parent enolates. Their utility is illustrated by the [2 + 2] cycloaddition to electron-deficient olefins, which, after hydrolytic workup, gives rise to the Michael addition
Use of methylenecyclopropanone ketals for cyclopentane synthesis. A new efficient thermal [3 + 2] cycloaddition
作者:Shigeru Yamago、Eiichi Nakamura
DOI:10.1021/ja00200a072
日期:1989.8
Synthese de [dimethyl-5,5 dioxannylidene-2]-3 cyclopentanecarboxylate de methyle a partir de dimethyl-6,6 methylene-1 dioxa-4,8 spiro [2.5] octane et de crotonate de methyle. Le crotonate de methyle peut etre remplace par d'autres esters (ex. heptene-2oate de methyle) ou par des lactones (ex. dihydro furannone-2). On obtient dans ce dernier cas des derives de cyclopenta [c] furannone
合成这些 de [dimethyl-5,5 dioxannylidene-2]-3 cyclopentanecarboxylate demethyle a partir dedimethyl-6,6 methylene-1 dioxa-4,8 spiro [2.5] 辛烷和 de crotonate demethyle。Le crotonate demethyle peut etre 替换 par d'autres 酯(例如庚烯-2oate demethyle)或内酯(例如二氢呋喃酮-2)。在 obtient dans ce dernier cas des 上推导 de cyclopenta [c] furannone
Synthesis of 2,2-Disubstituted Pentalenes and Indenes by a Useful Modification to Nakamura’s DMCP [3+2]-Cycloaddition Protocol
作者:Thomas Pettus、Todd Wenderski、Vincent DeNatale
DOI:10.1055/s-0029-1217755
日期:2009.10
A two-pot tactic is presented to reach the oxidized 2,2-dimethyl-substituted pentalene and indene ring systems.