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Cyclic Compounds Incorporating Two or Four Alkyne Units in Close Proximity – Theory and Experiments
Author(s) -
Gleiter Rolf,
Haberhauer Gebhard
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800072
Subject(s) - cyclobutadiene , chemistry , alkyne , ring (chemistry) , acetylene , bicyclic molecule , yield (engineering) , singlet state , triple bond , medicinal chemistry , stereochemistry , catalysis , double bond , computational chemistry , organic chemistry , molecule , excited state , physics , materials science , nuclear physics , metallurgy
In the first part we summarize the results of experiments performed with medium‐sized cyclic compounds (10, 12, 14 ring size) incorporating either two opposite acetylene units or two buta‐1,3‐diyne units. The acetylene units in the 10‐membered rings react either thermally or with the aid of Au I catalysis to afford bicyclo[4.4.0]‐1,6‐diene rings. Reduction with H 2 /Pd or addition of I 2 to 12‐membered rings containing two opposite buta‐1,3‐diyne units yield 5–6–5 cycles, whereas 14‐membered rings react with HCl to afford 5–8–5 or 6–6–6 rings. In the second part we discuss the results of calculations relating to 1,6‐transannular ring closure of cyclodeca‐1,6‐diyne derivatives in which the two triple bonds are each flanked either with two oxygen atoms or with two NH groups. For the resulting heterocycles, dicarbenes with singlet ground states are predicted. The extension of these model calculations led us to look at substituted phenylacetylenes (e.g., Ph–C≡C–OMe) for which dimerization to cyclobutadiene derivatives was predicted. This forecast could be verified by trapping the cyclobutadiene products with maleic acid.