Rearrangements in the Reduction of 3-Iodobicyclo[1.1.1]pentyl Azide with Lithium Aluminum Hydride:  Mechanistic Evidence of Intermediates

1,3‐Diethynylbicyclo[1.1.1]pentane, a Useful Molecular Building Block

“…It has been proven several times that whenever in the course of a reaction a reactive site, such as an anion, cation, radical, or carbene, emerges at the atom next to the strained bicyclopentane cage, the cage tends to rearrange. [21] This might also be the reason for the rearrangement in this particular case. [22] Further investigations of cycloaddition reactions in the close proximity of the bicyclopentane cage should respect this fact in general and prospective reaction partners need to be carefully chosen to avoid the problem.…”

“…173.4-174.8°C. 1 (17), 226 (12), 215 (9), 202 (5), 189 (21), 176 (4), 165 (18), 152 (11), 139 (14), 127 (30), 115 (19), 101 (7), 89 (6), 77 (20), 63 (8), 51 (9). HRMS (EI): calcd.…”

Selected Topics in the Syntheses of Bicyclo[1.1.1]Pentane (BCP) Analogues

“…Although this is the first reported example of successful isolation of the desired product, the difficulty of such reduction had been demonstrated by Timberlake and co‐workers in 2001 . When 25 was treated with relatively weak reductants (e. g. borane‐tetrahydrofuran complex), although the azido group was reduced to the corresponding amine, the alkyl‐iodide functionality was intact (not shown) . Ring‐opening by‐products were observed when relatively harsh reducing agents were used (e. g. lithium aluminum hydride) .…”

“…Bunker and co‐workers were able to reduce 25 to afford the desired 21⋅HCl , yet with low yield (16%) . Although this is the first reported example of successful isolation of the desired product, the difficulty of such reduction had been demonstrated by Timberlake and co‐workers in 2001 . When 25 was treated with relatively weak reductants (e. g. borane‐tetrahydrofuran complex), although the azido group was reduced to the corresponding amine, the alkyl‐iodide functionality was intact (not shown) .…”

Bicyclo[1.1.1]pentane‐Derived Building Blocks for Click Chemistry

“…It should be noted that to date, only a few papers have described syntheses of azides 2 ; they were prepared via a common synthetic intermediate 2a (R 1 = I) , . In turn, compound 2a was obtained by the reaction of propellane ( 1 ) with IN 3 , or via 1,3‐diiodopropellane ( 4 ), (Scheme ). A number of papers have described the synthesis and some selective reactions (e.g., Sonogashira coupling or silylation) of 1,3‐diethynyl[1.1.1]bicyclopentane ( 5 ); this compound was prepared in two steps from 1,3‐diacetylbicyclo[1.1.1]pentane ( 6 ) .…”