131190-09-5Relevant articles and documents
Pd-catalyzed intramolecular addition of active methylene compounds to alkynes with subsequent cross-coupling with (hetero)aryl halides
B?ocka, Aleksandra,Wo?nicki, Pawe?,Stankevi?, Marek,Cha?adaj, Wojciech
, p. 40152 - 40167 (2019/12/25)
We report an efficient protocol for tandem Pd-catalyzed intramolecular addition of active methylene compounds to alkynes, followed by subsequent cross-coupling with (hetero)aryl bromides and chlorides. The reaction proceeds under mild conditions, providing excellent functional group tolerance, including unprotected OH, NH2 groups, enolizable ketones, or a variety of heterocycles. Mechanistic studies point towards a catalytic cycle involving oxidative addition, intramolecular nucleophilic addition to the Pd(ii)-activated alkyne, and reductive elimination, with 5-exo-dig cyclization being the rate limiting step.
New cobalt-catalyzed cycloisomerization of ε-acetylenic β-keto esters. Application to a powerful cyclization reactions cascade
Cruciani, Paul,Stammler, Robert,Aubert, Corinne,Malacria, Max
, p. 2699 - 2708 (2007/10/03)
The full details of investigations into the cobalt(I)-catalyzed ene type reaction of ε-acetylenic β-keto esters to form highly functionalized methylenecyelopentanes are described. The observed regio-, chemo-, and stereoselectivities support a process of cycloisomerization which controls the relative stereochemistry of two contiguous stereogenic centers. An efficient route to the basic skeleton of the phyllocladane family has been achieved via a one-pot sequence of cyclizations: ene type, [2 + 2 + 2], [4 + 2]. This new cascade created six carbon-carbon bonds and four rings in a totally stereoselective manner from an easily accessible acyclic polyunsaturated precursor.
