名称:
Aromatische Spirane, 22. Mitt.: Darstellung von Cyclopenteno-4,5-indan-1-on und 2-Carboxymethyl-bzw. 4-Chlormethyl-indan als Synthone f�r Synthesen von anellierten 2,2?-Spirobiindanonen
摘要:
The title compounds were prepared as follows: tert.-butyl-indane (10) was formylated to give a 72:28 mixture of the aldehydes 23a and 23b which were submitted to a Knoevenagel-Doebner condensation to afford the cinnamonic acids 24. From the mixture, the pure stereoisomer 24a was obtained by one crystallization in 57% yield. Its methylester 27a could be quantitatively dealkylated to the methylester 8 by treatment with AlCl3 in toluene. Cyclization to the indanone 9 was then performed via the propionic acid 7 with polyphosphoric acid in 95% yield. From 9 the carboxymethyl derivative 30 was obtained by treatment with dimethylcarbonate and NaH. The second synthone 4-chlormethylindane (19) was prepared from the corresponding alcohol 18 (in 82% yield) which in turn could be obtained from methylester 17 by reduction with LiAlH4. The latter was accessible in 75% yield by dealkylation of ester 13.