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On Ring Carbomers of Cyclobutane, Cyclopentane, and Cyclodecane and Cyclization Reactions through Bis(alkynyl‐propargyl) Coupling
Author(s) -
Maurette Luc,
Godard Cyril,
Frau Silvana,
Lepetit Christine,
Soleilhavoup Michèle,
Chauvin Remi
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010316)7:6<1165::aid-chem1165>3.0.co;2-3
Subject(s) - cyclopentane , cyclobutane , propargyl , ring (chemistry) , chemistry , coupling (piping) , coupling reaction , medicinal chemistry , stereochemistry , organic chemistry , catalysis , materials science , metallurgy
A copper‐mediated procedure for terminal alkynyl‐propargyl coupling has been applied to “skipped” bis‐terminal undecatetrayne and 1,4‐bis(pseudo)halobut‐2‐ynes with the aim of preparing ring carbomers of representative strained and loose cycloalkanes, namely [ N ]pericyclynes. Two unprecedented, cyclic, “skipped” polyynes with CH 2 vertices have been isolated as mixtures of diastereoisomers: an isomer 1 b and a dimer 2 a of [5]pericyclyne 1 a . The isomer 1 b is a cyclotetrayne with an exocyclic allene function resulting from a unique formal S $\rm{_{N}^{\prime }}$ process. Its structure has been established by 1 H/ 13 C HMQC and HMBC two‐dimensional NMR analysis. According to density functional theory calculations, it is about 6 kcal mol −1 more stable than [5]pericyclyne ( 1 a ). Compound 1 b can also be regarded as a C13‐relaxed [4]pericyclyne, a long sought “skipped” C12 tetrayne. The dimer 2 a is a C30 ring that results from a formal S N process. It is a stable ring carbomer of cyclodecane, that is, a [10]pericyclyne, with four CH 2 vertices.