Reaction of 1-chloro-2-alkylcycloalkenes with organolithium reagents. A novel cyclopropanation reaction involving the generation of carbenes from vinyl halides

Suprafacial and Antarafacial Paths for the Thermal Vinylcyclopropane-to-Cyclopentene Rearrangement of 1-Ethenylbicyclo[4.1.0]heptane to Bicyclo[4.3.0]non-1(9)-ene

“…Cyclohexanone and PCl 5 afford 1-chlorocyclohexene ( 3 ); the corresponding organolithium compound and formaldehyde give 1-hydroxymethylcyclohexene ( 4 ) . A Simmons−Smith cyclopropanation reaction leads to 1-hydroxymethylbicyclo[4.1.0]heptane ( 5 ). − Oxidation of this alcohol gives an aldehyde ( 6 ) that may be converted through a Wittig reaction to 1-ethenylbicyclo[4.1.0]heptane ( 1 ) …”

“…[19][20][21] Oxidation of this alcohol 22 gives an aldehyde (6) that may be converted through a Wittig reaction 23 to 1-ethenylbicyclo-[4.1.0]heptane (1). 24 Aldehyde 6 served as well as synthetic intermediate for 1-ethynylbicyclo The gas-phase thermal reactions of 1, 1-d 2 , and E-1-d were run using a well-conditioned 300-mL kinetic bulb; 26 6 h at 338 °C was sufficient to achieve a 79% conversion of 1 to the vinylcyclopropane-cyclopentene rearrangement product 2 (70%; 89% yield) and several minor products (9%). The bicyclic olefin 2, a known compound, 27 was identified through proton and carbon-13 NMR spectroscopy.…”

“…The combined organic material was washed with water (15 mL), dried (MgSO 4), filtered, and concentrated. Column chromatography (silica gel, pentane) gave 0.96 g (65%) of 1 24 as a clear oil. A small sample was further purified by preparative GC (15% SE-30, 65 °C): 1 H NMR δ 5.48 (dd, J ) 17.3, 10.6 Hz, 1 H), 4.90 (dd, J ) 17.3, 1.3 Hz, 1 H), 4.84 (dd, J ) 10.6, 1.3 Hz, 1 H), 1.85-2.03 (m, 2 H), 1.71-1.81 (m, 1 H), 1.50-1.62 (m, 1 H), 1.11-1.48 (m, 4 H), 0.91-1.02 (m, 1 H), 0.67 (dd, J ) 9.3, 4.4 Hz, 1 H), 0.52 (dd, J ) 5.9, 4.4 Hz, 1 H) (compare ref 24); 13 C NMR δ 148.1, 108.4, 26.0, 23.8, 21.7, 21.6, 21.0, 20.3, 19.0; MS m/z (rel intensity) 122 (10, M + ), 107 (16), 93 (34), 79 (100), 67 (31), 53 (22), 39 (47).…”

Tricoordinate Organochromium(III) Complexes Supported by a Bulky Silylamido Ligand Produce Ultra‐High‐Molecular Weight Polyethylene in the Absence of Activators

“…Unless otherwise noted, reagents were obtained from commercial suppliers and used as received. Li[N(SiMe 3 )DIPP], vinyl lithium, BnK, and CrCl 3 · 3 THF were prepared according to literature procedures. The catalytic polymerization experiments were performed at the High Throughput Experimentation facility of the ETH Zürich (HTE@ETH) on a custom‐made 96‐parallel autoclave ( ILS GmbH ).…”

Anionic Reactions of N‐(trans‐2,3‐Diphenylaziridin‐1‐yl)imines and Their Use as 1,1‐Dipoles in Anionic Cyclizations

“…As shown in Scheme 5, apparently, intermediate 22b underwent a-elimination to yield carbene intermediate 23, from which a 1,2-H shift took place to produce the product 24b. [14] Further studies on sequential anionic cyclization and subsequent generation of carbene intermediates are planned.…”