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Benzoanellated centropolyquinanes, 11. Synthesis of tribenzotriquinacene and some centro ‐substituted derivatives
Author(s) -
Kuck Dietmar,
Lindenthal Thomas,
Schuster Andreas
Publication year - 1992
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19921250623
Subject(s) - chemistry , heterolysis , indene , yield (engineering) , aluminum hydride , lithium (medication) , bromide , stereochemistry , organic chemistry , medicinal chemistry , catalysis , medicine , materials science , methoxide , metallurgy , endocrinology
The syntheses of tribenzotriquinacene ( 1a ) and five centro ‐substituted derivatives, 1b–1e and 1g , as well as of the related diindan 13 are reported. The three‐step synthetic sequences include the reduction of suitably substituted 2‐benz‐hydryl‐1,3‐indandiones 3 to the corresponding 1,3‐indandiols 4 and the twofold cyclodehydration of the latter to close two additional five‐membered rings at a time. Although the yields of the cyclodehydration step 4 · 1 are only low to moderate (10–33%), the overall approach allows the preparation of 5–50‐gram amounts of the centropolyindans in most cases by starting from simple 1,3‐indandiones 2a–2c . This includes the new synthesis of the parent tribenzotriquinacene ( 1a ). The related C s ‐symmetrical diindan, 4b,9,9a,10‐tetrahydroindeno[1,2‐ a ]indene ( 13 ), has been prepared in high yield by using the same cyclodehydration technique. Scope and limitations of the double cyclodehydration strategy are described concerning the synthesis of 1,3‐indandiones with bulky substituents at C–2 and the cyclization of 1,3‐indandiols with an aptitude to undergo heterolytic cleavage of an exocyclic C–2–C‐α bond, in particular 4f . The course of the reduction of the 2,2‐disubstituted 1,3‐indandiones with lithium aluminum hydride is discussed on the basis of the stereochemistry of the product 1,3‐indandiols.