Diversity-oriented approach to linearly fused spirocycles via strategic utilization of a [2+2+2] cycloaddition and the Diels–Alder reaction
摘要:
We have demonstrated a simple and an efficient protocol for assembling a library of linearly fused spirocycles in a diversity-oriented manner by utilizing two sequential atom-economic reactions such as a [2+2+2] cycloaddition and the Diels-Alder (DA) reaction. Herein, we have used rongalite for the formation of sultine derivatives, which are useful latent diene equivalents suitable for the DA sequence to generate a library of polycycles under mild reaction conditions. (C) 2015 Elsevier Ltd. All rights reserved.
see text] A 2-(2,6-diisopropylphenyl)iminomethylpyridine (1a)/CoCl(2).6H(2)O/Zn reagent has been developed as an effective instant catalyst for the intra- and intermolecular cyclotrimerization of alkynes to substituted benzenes, making the method extremely practical since the reagent, 1a/CoCl(2).6H(2)O/Zn, is inexpensive and easy to handle and the reaction is less sensitive to moisture and is reasonably
combination of cationic rhodium(I) complexes with N-phosphino tert-butylsulfinamides (PNSO) ligands is efficient for catalytic intra- and intermolecular [2+2+2] cycloaddition reactions. PNSO ligands are a new class of chiral bidentate ligands, which have the characteristic of combining the easily accessible sulfur chirality with the coordinating capacity of phosphorous. Cycloaddition of open-chained and
Disclosed is a process for production of a substituted benzene, which comprises intramolecularly and/or intermolecularly trimerizing a triple bond in an alkyne in the presence of a transition metal catalyst to yield a substituted benzene compound. In the process, the transition metal catalyst is prepared from an iminomethylpyridine represented by the formula (1) or (2), a transition metal salt or a hydrate thereof, and a reducing agent in a reaction system and is used to perform the trimerization. The process can be used in any one of the intramolecular cyclization of a triyne compound, the cyclization of a diyne compound or an alkyne compound and the intermolecular cyclization of three molecules of an alkyne compound, is excellent in economic effectiveness and operability, and is practically advantageous.
wherein R
1
and R
3
independently represent a linear or cyclic C
1
-C
20
aliphatic hydrocarbon group or the like; R
2
represents a hydrogen atom or the like; X represents a hydrogen atom, O or the like; and Y represents O, S or the like.