1 1,2-dimethylcy clopropane

Make molecular models of c/s and trans 1 2 dimethylcy clopropane and compare their strain energies... 

Hydrogenation of l-isopropenyl-2,2-dimethylcyclopropane (94) over 5% Pd-C gives the ring-opened products only, while over 5% Pt-C and 5% Rh-C, the hydrogenation of the isopropenyl group occurs predominantly to give 1-isopropyl-2,2-dimethylcy-clopropane as the main product (eq. 13.146).284... 

Neopentyl chloride to HC1+ 1,1 -dimethylcy clopropane -fmethylbutenes+isobutene-t-CH +CHjCI+chlorinated isobutenes gas phase, static (410-496) unimolecular-I-radical chain (3/2 order). HCl catalysed. For chain reaction A = 3.5xl0 E = 56.3 567... 

HjC = C = CHMe MejCNj A syn- and a n-2-ethylidene-l,l-dimethylcy-clopropane and l,l,2-trimethyl-3-methyl-enecyclopropane and l-isopropylidene-2-meth-ylcyclopropane 143... 

MeHC=C = CHMe MeCHNj A CIS- and trans-l-ethylidene-2,3-dimethylcy-clopropane 143... 

Tomoskozi, I., Absolute configuration and partial asymmetric synthesis of 2-phenyl-l,l-dimethylcy-clopropane, Tetrahedron, 22, 179, 1966. 

The first generation process started with the chemical synthesis of the (R,S)-amide. There were several possible synthetic routes (Fig. 8) via the (R,S)-nitrile or (R,S)-acid [19, 20], A microbial screening program resulted in the isolation of several bacterial strains containing amidases that could specifically hydrolyze the (R)-amide. One of these strains, Comomonas acidivorans A 18 was particularly effective [21]. After the hydrolysis of the unwanted isomer the product (S)-2,2-dimethylcy-clopropane carboxamide was isolated from the bio-solution using a combination of salting-out and solvent extraction. This process had some intrinsic problems ... 

Fig. 9 Process scheme for the production of (S)-2,2-dimethylcy-clopropane carboxamide.

Which compound would you expect to be the more stable c/5-l,2-dimethylcyclopropane or fran5-l,2-dimethylcy-clopropane Explain your answer. 

The 9,10-dicyanoanthracene (DCA)-sensitized c/s,tram-photoisomerization of highly electron-rich 1,2-diarylcyclopropanes and diarylmethylenecyclopropanes efficiently proceeds via a radical cation chain transfer mechanism.The photoisomerization of electron-rich l-diarylvinylidene-c/s-2,3-dimethylcy-clopropane (c-2d) in acetonitrile was also sensitized by DCA via photoinduced electron transfer. The photoisomerization efficiently takes place to give a 3 7 PSS mixture of c-2d and t-2d. However, the less electron-rich 1-diarylvinylidenecydopropanes c-2a-c under the same reaction conditions slowly isomerized... 

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