Cyclopropyl Building Blocks for Organic Synthesis. Part 85. A Versatile Access to 1‐Cyclopropyl‐2‐aryl‐1,3,5‐hexatrienes — Domino Heck—Diels—Alder Reactions of 1,3‐Dicyclopropyl‐1,2‐propadiene.

Abstract

Cyclopropane derivatives Cyclopropane derivatives Q 0021Cyclopropyl Building Blocks for Organic Synthesis. Part 85. A Versatile Access to 1-Cyclopropyl-2-aryl-1,3,5-hexatrienes -Domino Heck-Diels-Alder Reactions of 1,3-Dicyclopropyl-1,2-propadiene. -An efficient three-step synthesis of the allene (V) is described. It is found to undergo Pd-catalyzed domino Heck-Diels-Alder reaction with aryl halides and dienophiles via hexatriene intermediates. - (KNOKE, M.; DE MEIJERE*, A.; Synlett 2003, 2, 195-198; Inst. Org. Chem.,

The Heck Reaction Applied to 1,3- and 1,2-Unsaturated Derivatives, a Way towards Molecular Complexity

“…1,3-Dicyclopropyl-1,2-propadiene ( 35 ) was coupled with several aryl iodides and bromides under palladium catalysis in the presence of a dienophile which underwent a domino Heck–Diels–Alder reaction. 3-(1’-Arylalkenyl)-substituted cyclohexenes 37 were achieved in moderate to good yields [ 24 ]. Then the methodology was extended to differently substituted cyclopropylallenes [ 25 ].…”

1,3- and 1,2-Unsaturated Derivatives as Valuable Synthetic Tools in Organometallic Syntheses

“…1,3-Dicyclopropyl-1,2-propadiene was coupled to various aryl halides, and the 1,3,5-hexatrienes 137 produced after a very fast cyclopropylcarbinyl to homoallyl rearrangement, were trapped with different dienophiles in a domino Heck DielsAlder reaction. 45 The synthesis, proposed by de Mejieere et al, was extended to several cyclopropylallenes and yielded oligosubstituted cyclohexene derivatives 138 (Scheme 50). Surprisingly, the [4 + 2] cycloaddition was found to proceed in a non-concerted fashion with a preference for the thermodynamically more stable trans, trans isomer which cannot be formed in a concerted DielsAlder reaction.…”