1559reh18323-34311/3/0511:12Pag0331 EQA Solutions to Problems331 uamaa-a 0 CH: CHO 42 and 43.(a)CH,CHO CH,CHCH.CHO OH OH CH;-CH-CH2-CHO CH:CH2CH2-CH-CH-CHO CH-CH OH OH CH3-CH-CH-CHO CH;CH2CH2-CH-CH2-CHO CH.CH340. 41. Aldol condensations. The direction of nucleophilic attack is shown, and the new bond is marked in the product with an arrow. (a) (b) (c) (d) 42 and 43. (a)
CH3CHO  CH3CH2
CH2CHO None of these compounds will be a “major” product, but the first one may form in somewhat higher yield than the others because it is the least sterically crowded. OH CH3 CH CH2 CHO CH2 CHO OH CH3 CH CH2CH3 CH3CH2CH2 CH CHO OH CH CH CH2CH3 CHO CH3CH2CH2 OH CH H O H OH C CHO  CHO HCC(CH3)2CH2CH2CHCCH3 CH3 CH3 CH3 O O OH O H  (CH3)2CCHO CH3CH3 C H C O CH CHO OH   CH2 C H CHCHO CHCHO O CH2CH OH   OH O O H O HOOH O  OH O H H   OH O H   O Solutions to Problems • 331 1559T_ch18_323-343 11/3/05 11:12 Page 331