W. M. LAUERAND NICOLASBRODOWAY
5406
[CONTRIBWTTONFROM THE SCHOOL O F CHEMISTRY OF
VOl. 75
UNIVERSITY OF MINNESOTA]
THE
The Transetherificationof Ethyl 0-Ethoxycrotonate with Cinnamyl Alcohol BY W. M. LAUERAND NICOLAS BRODOWAY~ RECEIVED JUNE29, 1953 Transetherification of ethyl 0-ethoxycrotonate with cinnamyl alcohol gives ethyl a-(a-phenylally1)-acetoacetate. Since inversion of the cinnarnyl group takes place, it is assumed that ethyl 6-cinnamoxycrotonate is first produced and that it rearranges under the conditions present during transetherification. Earlier attempts to prepare ethyl 8-cinnamoxycrotonate apparently yielded its rearrangement product ethyl a-(a-phenylally1)-acetoacetate.
Transetherification of p-ethoxyacrylates with allyl alcohols yields p-alloxyacrylates, which are capable of undergoing rearrangement. Accordingly, ethyl P-ethoxyacrylate (I) is converted to ethyl 8-alloxyacrylate (11) and ethyl a-formylallylacetate (111) upon heating with allyl alcohol in the presence of sodium bisulfate.2 CzHbO--CH=CHCOOCzH6 I CHz=CH-CHz&CH=CHCOOC~Hs I1
CHpCH-CH-CHzCOOH
I
C6Hs VI1 CHa--C-CHCOOCaHs
CHa-C=CH*
I
I
O-CHrCH=CHCas VI11
O-CH&H=CHC& IX
present study indicates that the compound ClrH~80t is ethyl CY-( a-phenylallyl)-acetoacetate (X) and that the enol ether VI11 is in reality (a-phenylally1)acetone (XI)
TI
H
CHI-C-CH-COOGH~
I
O=C-CHCOOCgH6
I
CHzCH=CHz I11
The application of transetherification in the case of ethyl p-ethoxycrotonate (IV) and y, y-dimethylallyl alcohol yields the rearrangement product, ethyl a-(ala-dimethylally1)-acetoacetate(VI). In this case the intermediate y, y-dimethylallyl enol ether (V) could not be isolated, but the fact that formation of the product VI involved inversion of the allyl group points to the occurrence of the y,y-dimethylallyl enol ether as an intermediate in the formation of the product.3 CH~-C=CHCOOC~HS
I
OCzHs IV
CH,-C=CHCOOCzHs
I
OCHzCH=C( CH8)z V CHS-C-CHCOOC~H~
/I
I
0 C( CHs)2CH=CH2 VI
This case is of particular interest since it involves the inversion of a y, y-dialkylallyl group without the intervention of abnormal rearrar~gement.~ The interaction between ethyl 8-ethoxycrotonate and cinnamyl alcohol was investigated by Bergmann and C ~ r t e . The ~ main product, C15H180aJ upon alkaline hydrolysis yielded two products, (1) P-phenyl-p-vinylpropionic acid (VII) and (2) a compound, C12Hlr0, which they designated as cinnamyl isopropenyl ether (VIII). On this basis, the compound ClsHlaOa was regarded as ethyl 0-cinnamoxycrotonate (IX) and it was believed that, on treatment with alkali, some rearrangement with inversion of the cinnamyl group had occurred. The (1) This paper is based on part of the Ph.D. Thesis, 1953, of Nicolas Brodoway. (2) W. J. Croxall and J. 0.VanHook. THISJOIJRNAL, 72, 803 (1950). ( , 3 ) K. Brack and 1%.Schinz. lI?11
