The 1,3,4-Oxadiazole and 1,3,4-Thiadiazole Coupling of Norbornenes and 7-Oxanorbornenes under High Pressure: New Structures, Mechanistic Detail and Synthetic Applications

Rigid Alicyclic Molecules from Bicyclo[2.2.1]hept‐2‐enes (=8,9,10‐Trinorbornenes) and 1,4‐Dipyridin‐2‐ylphthalazines as Stereoselective Coupling Agents

“…-A particularly effective way of linking two 8,9,10-trinorbornenes (¼ bicyclo[2.2.1]hept-2-enes) [1] involves the coupling of fused trinorbornenes with 2,5-bis(trifluoromethyl)-1,3,4-oxadiazole [2]. The oxadiazole coupling delivers a new 7-oxabicyclo[2.2.1] moiety at a junction of two trinorbornene units (see A, Fig.…”

Thiadiazoles

“…Analogously, the reaction of 354 with tosyl cyanide (358) leads to the key intermediate 359, which, by displacement of the tosyl group with ammonia, provides the 5-amino-1,2,4-thiadiazoles 360 (Scheme 14.93) [203]. [207].…”

“…In particular, 2,5-bis(trifluoromethyl)-1,3,4-thiadiazole (806) has been used as 4p component in a Diels-Alder reaction, giving rise with norbornadiene to bicycloadduct 809. The formation of this compound was rationalized via the initial cycloadduct 807, which loses molecular nitrogen to generate a thiocarbonyl ylide (808) that reacts with a second molecule of norbornadiene (Scheme 14.231) [358].…”

High‐Pressure Assisted Synthesis of Fused Norbornenes Containing Two7‐Metallonorbornene Units

“…A synthesis of adducts of this type, containing a 7-silanorbornene ring condensed with various 7-oxanorbornene derivatives, was recently developed in one of our research groups. [7][8][9][10][11] In this work we report on the synthesis of more complex molecules containing two 7-sila-or 7-germanorbornene moieties. Two types of bis-dienophiles -the 1,4:5,8-diepoxy-1,4,5,8-tetrahydronaphthalene derivatives 4 [12] and 5 [13] [ [14] and its dimethyl derivative 7 [14] -were selected for this purpose (Scheme 1).…”