| abstract |
The present invention provides compounds having the structure: ##STR1## wherein R 1 represents alkoxy or aralkoxy, R 2 represents hydrogen, alkoxy, aralkoxy, alkyl, aralkyl, or R 1 and R 2 taken together represent the group --O--CH 2 --O--, R 3 represents hydrogen, alkyl, aralkyl, acyl or a protecting group, Y represents Cl, Br, I or a leaving group; and X represents Cl, Br or I. n The present invention also provides a process for preparation of compounds VI in a single step wherein X and Y are the same and represent Cl, Br, ,or I, and R 3 is as previously defined except that in this instance, it does not represent a protecting group. n According to another aspect of the present invention there are provided compounds VII-a and VII-b having the structure: ##STR2## wherein R 1 , R 2 and R 3 are as previously defined, j is an integer having a value of 0 or 1, Z 1 represents a non-reacting electron withdrawing group, and Z 2 represents a non-reacting electron withdrawing group or hydrogen, R 8 and R 9 are the same or different and represent hydrogen, alkyl, aralkyl, alkoxy, or aralkoxy, and R 7 represents hydrogen, alkyl, aralkyl or acyl. Compounds VII-a may be prepared from compounds VI through the use of the process of "insertion-cyclization" which is provided by another aspect of the present invention. n According to a further aspect of the present invention, compounds VII-a are converted into tetralone III-a shown below: ##STR3## wherein R 1 , R 2 , R 3 , Z 1 , Z 2 , R 7 , R 8 and R 9 are as previously defined. Certain of these compounds can, in turn, be readily converted into picropodophyllin and picrosikkimotoxin. The latter can be converted into known antineoplastic agents by known procedures. |