BY CYCLODEHYDRATION TO CENTROPOLYINDANES - DEVELOPMENT OF A NOVEL CLASS OF INDANE HYDROCARBONS WITH 3-DIMENSIONAL MOLECULAR FRAMEWORKS USING A CLASSICAL SYNTHETIC TOOL

Cyclodehydration of suitably 2-benzyl-substituted indan-1-ols and inda n-1-ones and related compounds is a key synthetic tool for the highly efficient construction of three-dimensional carbocyclic frameworks con taining several centrically condensed indane units. Inspired by a fort uitous cyclodehydration observed as a side reaction, this investigatio n has been spanned from two-fold cyclodehydration of 19-indanediols to ''bicyclodehydration'' of 1-indanones and 1,3-indanediones and to som e directed applications of cyclodehydration of C-s-diindanols, C-s-dii ndanones, and C-s-diindanolones with sterically preoriented phenyl gro ups. Benzo-anellated triquinacenes and fenestranes, in particular, hav e become directly accessible by two-fold cyclodehydration, the latter including all-cis- but also cis,cis,cis,trans-fenestrane stereoisomers . Notwithstanding some limits of the strategy, the broad applicability of two-fold pentaannulation by cyclodehydration has led to the develo pment of an entire class of novel polycyclic hydrocarbons, the ''centr opolyindanes''.