A series of fused tetracycles with a benzene or cyclohexadiene core (2a–h) is satisfactorily prepared by intramolecular [2 + 2 + 2] cycloadditions of triynic and enediynic macrocycles (1a–h) under RhCl(PPh3)3 catalysis; the enantioselective cycloaddition of macrocycles1b and 1e gives chiral tetracycles with moderate enantiomeric excess.
Ruthenium-Catalyzed [2 + 2] Cycloadditions between Norbornene and Propargylic Alcohols or Their Derivatives
作者:Gavin C. Tsui、Karine Villeneuve、Emily Carlson、William Tam
DOI:10.1021/om500563h
日期:2014.7.28
Diastereoselective ruthenium-catalyzed [2 + 2] cycloadditions of norbornene and propargylic alcohols or their derivatives were investigated. The cycloadditions were found to be highly stereoselective, giving exo cycloadducts in moderate to excellent yields with diastereoselectivities up to 92:8. When a chiral propargylic alcohol was used in the cycloaddition, up to 80% ee of the [2 + 2] cycloadducts was
Stereoselective synthesis of substituted dienes by the double ortho ester Claisen rearrangement
作者:Suk-pyo Hong、Sung-jun Yoon、Byung-chan Yu
DOI:10.1016/j.tetlet.2004.12.015
日期:2005.1
This letter shows the highly stereoselective synthesis of substituted (E)-1,3-dienes from substituted propargylic diols via the double ortho ester Claisenrearrangement. The cyclohexyl-substituted diene undergoes thermal Diels–Alder cycloaddition with maleic anhydride to produce the corresponding bicyclic diester in highly stereoselective manner.
Synthesis and Properties of 2,3‐Diethynyl‐1,3‐Butadienes
作者:Madison J. Sowden、Jas S. Ward、Michael S. Sherburn
DOI:10.1002/anie.201914807
日期:2020.3.2
The first general preparative access to compounds of the 2,3-diethynyl-1,3-butadiene (DEBD) class is reported. The synthesis involves a one-pot, twofold Sonogashira-type, Pd0 -catalyzed coupling of two terminal alkynes and a carbonate derivative of a 2-butyne-1,4-diol. The synthesis is broad in scope and members of this structural family are kinetically stable enough to be handled using standard laboratory
sustainable, highly regiospecific substituted pyrroles were synthesized using a well-defined, air stable, molecular iron(0) complex. The developed methodology is broadly applicable and tolerates a variety of functional groups. C-2, C-3, and C-2 & C-4 substituted pyrroles were synthesized in good yield. Symmetrical bis-pyrroles were accessible for the first time using an ironcatalyst. On the basis of the experimental