32364-41-3Relevant academic research and scientific papers
Total Synthesis of Gelsemoxonine through a Spirocyclopropane Isoxazolidine Ring Contraction
Diethelm, Stefan,Carreira, Erick M.
supporting information, p. 6084 - 6096 (2015/05/27)
Plants of the species Gelsemium have found application in traditional Asian medicine for over a thousand years. Gelsemoxonine represents a novel constituent of this plant incorporating a highly functionalized azetidine at its core. We herein report a full
Rhodium-catalyzed carbonylative [3 + 2 + 1] cycloaddition of alkyne-tethered alkylidenecyclopropanes to phenols in the presence of carbon monoxide
Kim, Seyun,Chung, Young Keun
supporting information, p. 4352 - 4355 (2015/01/09)
A novel Rh-catalyzed carbonylative [3 + 2 + 1] cycloaddition of alkyne-tethered alkylidenecyclopropanes for the facile synthesis of bicyclic phenols in high yields has been developed. The reaction tolerated carbon and heteroatoms in the tether.
Versatile Synthesis of Enantiomerically Pure 2-Alkoxy-1-ethynylcyclopropanes and Their Application in the Synthesis of Enantiomerically Pure Bicyclo-oct-1-en-3-ones
Braese, Stefan,Schoemenauer, Sten,McGaffin, Gregory,Stolle, Andreas,Meijere, Armin de
, p. 545 - 555 (2007/10/03)
A variety of chiral, nonracemic 2-alkoxy-1-alkynylcylopropanes 7 were synthesized in good to very good yields from enantiomerically pure glycidol derivatives (glycidol tosylate, epichlorohydrin) by boron trifluoride promoted addition of lithium trimethyls
Nucleophilic substitutions of 1-alkenylcyclopropyl esters and 1-alkynylcyclopropyl chlorides catalyzed by palladium(0)
Stolle, Andreas,Ollivier, Jean,Piras, Pier Paolo,Salaün, Jacques,De Meijere, Armin
, p. 4051 - 4067 (2007/10/02)
The 1-ethenylcyclopropylsulfonates 2e,f and 2-cyclopropylideneethyl esters 10b,c, readily available from cyclopropanone hemiacetal 1, undergo regioselective Pd(0) catalyzed nucleophilic substitution via the unsymmetric 1,1-dimethylene-π-allyl complex 23. With stabilized anions (enolates of malonic ester, β-dicarbonyl compounds, β-sulfonyl ester, and Schiff bases as well as acetate anion, sulfonamide anion, etc.) the nucleophilic substitution occurs at the terminal vinylic position exclusively, providing cyclopropylideneethyl derivatives as building blocks of high synthetic potential. Competition experiments have disclosed that 1-ethenylcyclopropyl tosylate (2e) and cyclopropylideneethyl acetate (10b) are more reactive than dimethylallyl acetates 19 and 22, respectively. Use of chiral phosphines as ligands in the palladium catalyst can provide optically active methylenecyclopropane derivatives. With phenyl-, methyl-, and even n-butylzinc chloride as nucleophiles, the reaction apparently proceeds with initial transfer of the organic residue to palladium, followed by reductive elimination entailing tertiary substitution on the cyclopropane ring exclusively; the same type of product is obtained with azide and bis(trimethylsilyl)amide. But the site of hydride attack to yield reduction products depends on the hydride source. 1-Alkynylcyclopropyl chlorides 12, 13, and 14 react only with organozinc chlorides (nonstabilized nucleophiles) to provide mixtures of ethenylidenecyclopropanes 65 and alkynylcyclopropanes 66, via the σ-palladium complexes 69 and 70, while chloride 15 undergoes mainly reduction. Other transition metal catalysts (Ni, Mo) also induce substitutions, but with poorer regioselectivity.
Palladium(0) catalyzed substitution reactions of cyclopropyl group containing allylic esters
Stolle, Andreas,Salauen, Jacques,De Meijere, Armin
, p. 4593 - 4596 (2007/10/02)
Complete regioselectivity is observed in palladium(0) catalyzed allylic substitution reactions of 1-vinylcyclopropyl 3 and cyclopropylldeneethyl esters 6 with a series of soft carbon nucleophiles to give γ-cyclopropylidene-1,3-dicarbonyl and 1-carbonyl-2-sulfonyl compounds. Highly functionalized mathylenecyclopropanes are thus obtained in good to excellent yields from easily accessible 1-vinylcyclopropyl tosylates 3d.
