Ketene Acetals. VIII. The Reaction of Ketene Diethylacetal with α,β-Unsaturated Carbonyl Compounds

The Ketene Acetals.

“…15, table 1) or even exceeds (Nos. 14, 18, 19, and 20) that of the orthoester, which has a substantially higher molecular weight.…”

Reactions of the zwitterions from trisubstituted electron-deficient ethylenes and electron-rich olefins

“…The reaction mixture was extracted with 100 ml of ether. From this solution were isolated 0.05 g of l,l-dicyano-2-7V,7V-dimethylaminoethylene (11) and 0.25 g of 1 -, -dimethylamino-1 -cyano-2-methylpropane (13) (containing a very small amount of 11). Distillation of 13 gave a pure sample: bp 60°( 25 mm) [lit.21 54°( 1 mm)]; ir (NaCl neat) 2815, 2770 (Me2N-), 2240 and 2220 (vw, C=N); nmr (CDCI3) 6.9-7.15 (two d, 1 FI a to C=N and Me2N), 7.72 (s, 6 H, Me2N), 7.87-8.40 (m, 1 a to the 2 Me), 8.83-9.07 (two d, Me a to C-H); from the nmr spectrum, it seems there were two rotational isomers; mass spectrum (m/e, %) •+ (126, 52), •+ -HCN (99, 21), M-+ -CH2=N-Me (83, 100).…”

The Diels-Alder Diene Synthesis.

“…1,3-Cyclohexadiene (198) gives V. By way of comparison, cyclopentene (336) gives VI and cyclohexene (198) gives VII. Dimethylmaleic anhydride does not react, and the reactions with p-benzoquinone and with benzalacetophenone proceed normally to give cyclobutane derivatives, but acetylenedicarboxylic ester yields 3,5-diethoxyphthalic ester (415).…”

“…react in a unique manner with certain dienophiles.Condensation between 2 moles of ketene diacetal and 1 mole of maleic anhydride gives a diethoxydihydrophthalic anhydride(415): i v i d u a l n o t d i r e c t l y a s s o c i a t e d w i t h s c i t e i s p r o h i b i t e d .…”