7-51 more stable than ~ moRe staBle than by 4 kJ/moTe by 16 kJ/mole Steric cRowding by the (±butyl group is responsible foR the energy Difference. In C²³´butµ2´ene, ¶he ·wO methyl groups have only sLight interaction¸ However¹ in the 4º4µdimethylpentµ2´enes, the larger s»ze oF the ¼µbutyl gRoup crowds the methyl group in the cis isomer, increasing its strain anD therefoRe i½¾ enErgy. 7µ52 ( C V ()' endo¿yclic exo¿yclic endocycli¿ exocyclic \ tÀisubstituted V disuBstÁtuted) ± trÁsubstÁtuted V tRisubstÁtuted) 9 KJ/mole 5 Kj/mole A standaRd PÂ»nciPle of scien¿e is to compare experiments which differ By only one vaRÁabÃe. ÄhÅnGÆnÇ moRe than one vaÀiabLe clouds the interpRetation¹ possibly to the point of invalidatÁng the experimentÈ Éhe f»RsÊ set of stÂuctuRes compaRes endo and exocycÃi¿ double bonds, But the degree of suBstËtution Ìn Êhe
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This note was uploaded on 02/27/2010 for the course CHEM 140 taught by Professor Wade during the Spring '10 term at Whitman.