Coupling-isomerization-Claisen sequences - mechanistic dichotomies in hetero domino reactions

A new coupling - isomerization - Claisen domino reaction starting from electron deficient halides and 1-(hetero)aryl propargyl trityl ethers dichotomizes in the concluding steps of the sequence and gives rise to the formation of tricyclo[ 3.2.1.0(2,7)] oct-3-enes, enones, 1H-isochromenes, or indans as a consequence of minute differences of substituent effects.