Get Bridged Aromatic Compounds PDF

By Brandes H. Smith (Eds.)

ISBN-10: 0123957486

ISBN-13: 9780123957481

Show description

Read Online or Download Bridged Aromatic Compounds PDF

Similar nonfiction_11 books

New PDF release: Hysteresis Effects in Economic Models

This quantity is dedicated to the hysteresis phenomenon in financial relationships. This subject has bought renewed consciousness in economics specifically within the overdue eigh­ ties. because the factor isn't really settled there's nonetheless a transforming into literature on it. the purpose of this quantity is to summarize the findings, current new effects, and to attract realization to extra learn.

Additional resources for Bridged Aromatic Compounds

Example text

4C A 1 C 1 3 in ether. AICI3 in carbon disulfide. Finely divided A 1 C 1 3 in carbon disulfide—ether. (LXX) to behavior noted already in the cyclophanes. "Ortho" cyclization occurs first. When steric or conformational conditions preclude "ortho" cyclization but the chain length is too short for "meta" [to (LXIX)], a dimer (or in some cases no cyclic product) is the result. Finally substitution occurs at the next possible site. The Friedel-Crafts Cyclization Method 59 Two items, at least, appear t o be wrong in the above scheme.

4]paracyclophane (17). 5]paracyclophanes by the same general procedure (45). The diester precursor, (X), was prepared as follows: the α,ω-diphenylalkane was both Η mono- and diacetylated with the monoacetyl derivative then being propionylated and both diketones converted to diacids by the Willgerodt reaction, to diesters by the usual means, and to the saturated diester by catalytic hydrogenation. 5]paracyclophane (all, remember, are the perhydro compounds). The yield here clearly improved as the strain decreased.

Hansley (24,25) was the first to report a marked improvement in the acyloin yield through use of highly purified xylene or toluene as solvent and the maintenance of a temperature sufficient to keep the sodium metal molten and thus more easily and thoroughly dispersed. It was also suggested that an inert gas atmosphere be used. With these improvements Hansley showed the usefulness of the acyloin cyclization for carbocyclic rings of 12-36 members. Some years later Prelog et al, in their quest for improved synthetic routes to C 9 - C 12 rings, reinvestigated the work of Hansley and suggested additional modifications (26).

Download PDF sample

Bridged Aromatic Compounds by Brandes H. Smith (Eds.)


by George
4.0

Rated 4.00 of 5 – based on 13 votes