K-methane rearrangement

Dibenzocyclopentanemethylene derivative 44 undergoes photosensitized-oxa-di-K-methane rearrangement to give 45 in 96 % yield [47]. 

Singh, V.K., Deota, RT., and Bedekar, A.V., Studies in the synthesis of polycyclopentanoids synthesis, oxa-di-7i-methane rearrangement of annulated bicyclo[2.2.2]octenones and cyclopropane ring cleavage of tetracyclo[6.3.0.0. > 0 > ]undecenones,/. Chem. Soc., Perkin Trans. 1, 903,1992. 

Example describes the synthesis of acetylene (C2 H2) from calcium carbide (CaC2). Modem industrial production of acetylene is based on a reaction of methane (CH4) under carefully controlled conditions. At temperatures greater than 1600 K, two methane molecules rearrange to give three molecules of hydrogen and... 

We are asked to calculate and compare the pressures of methane gas using the van der Waals equation (Equation ) and the ideal gas equation (F V = K F TJ. Van der Waals constants a and b must be looked up in a data table such as Table 11-1. To calculate pressures, we rearrange the van der Waals equation... 

Tetraethynylmethane (39), a potential monomer for a three-dimensional superdiamonoid carbon network [1], was elusive for many years [51, 52], until its synthesis was accomplished in 1993 by Feldman and co-workers [53]. The key step in the synthesis was the acid-mediated Johnson orthoester variant of the Claisen rearrangement, which provided the central quaternary methane C-atom with suitable functional groups for the ultimate transformation into 39 [Scheme 13-9(b)]. Solid 39, like tetraethynylethene (20), decomposes rapidly at room temperature in either the presence or absence of oxygen. The earlier efforts to prepare tetraethynylmethane had yielded the peralkynylated derivatives 40-42 [Scheme 13-9(c, d)] [51, 52]. Tetraethy-nylallene represents another potential precursor for a three-dimensional carbon network [1], but remains elusive of the perethynylated [K]cumulenes, so far only the silyl-protected [3]cumulenes 43a and 43b [Scheme 13-9 (e)] have been prepared [54]. With 44 [Scheme 13-9 (f)], the first transition metal complex of a perethynylated ligand is now available [55]. 

McClure, C.K., Link, J.S., and Kiesshng, A., The oxa-di-7t-methane photochemical rearrangement of quinuchdinones, 1- and 2-aza-3-carboxybicyclo[2.2.2]oct-2-ene-5-ones Application to the synthesis of pyrrohzidine alkaloids. Abstract no. ORGN 480,221" ACS Meeting, San Diego, CA, 2001. 

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