Synthesis and Structures of [2.n]Metacyclophan‐1‐enes and their Conversion to Highly Strained [2.n]Metacyclophane‐1‐ynes. Issue 27 (10th July 2020)

• Record Type: Journal Article
• Authors: Akther, Thamina; Islam, Md. Monarul; Kowser, Zannatul; Matsumoto, Taisuke; Tanaka, Junji; Rahman, Shofiur; Alodhayb, Abdullah; Georghiou, Paris E.; Redshaw, Carl; Yamato, Takehiko
• Is Part Of: European journal of organic chemistry. Issue 27(2020)
• Page Start: 4167
• Page End: 4175
• Publication Date: 2020-07-10
• Subjects: [2.n]Metacyclophane‐1‐ynes -- Strained molecules -- Diels–Alder reaction -- DFT calculation; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202000548
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : The syntheses of syn ‐[2. n ]metacyclophan‐1‐enes ( n = 5, 6, 8) in good yields using the McMurry cyclization of 1, n ‐bis(3‐formyl‐4‐methoxyphenyl)alkanes are reported. Conversion of syn ‐[2.6]‐ and [2.8]metacyclophan‐1‐enes to the corresponding highly strained syn ‐type [2.6]‐ and [2.8]metacyclophane‐1‐ynes was achieved by successive bromination and dehydrobromination reactions. An attempted trapping reaction of the putative corresponding [2.5]metacyclophane‐1‐yne by Diels–Alder reaction with 1, 3‐diphenylisobenzofuran failed due to its smaller ring size and strained structure. X‐ray crystallographic analyses show that the triple bonds in syn ‐[2.6]‐ and [2.8]metacyclophane‐1‐ynes are distorted from linearity with bond angles of 156.7° and 161.4°, respectively. A DFT (Density Functional Theory) computational study was conducted to determine the stabilities of different conformations of the target compounds. Abstract : Synthesis and structures of [2. n ]metacyclophan‐1‐enes and their conversion to highly strained [2. n ]metacyclophane‐1‐ynes, in which the triple bonds are distorted from linearity with bond angles of 156.7°–161.4°, are discussed.