Rhodium‐Catalyzed Chemo‐, Regio‐, Diastereo‐, and Enantioselective Intermolecular [2+2+2] Cycloaddition of Three Unsymmetric 2π Components

Abstract

We have developed the Rh + /H 8 -binap-catalyzed chemo-, regio-, diastereo-, and enantioselective intermolecular [2+2+2] cycloaddition of three unsymmetric 2π components. Thus, two arylacetylenes react with a cis-enamide to yield a protected chiral cyclohexadienylamine. Moreover, replacing one arylacetylene with a silylacetylene enables the [2+2+2] cycloaddition of three distinct unsymmetric 2π components. These transformations proceed with excellent selectivity (complete regio-and diastereoselectivity and up to > 99 % yield and > 99 % ee). Mechanistic studies suggest the chemo-and regioselective formation of a rhodacyclopentadiene intermediate from the two terminal alkynes.

Ir/Zn-cocatalyzed chemo- and atroposelective [2+2+2] cycloaddition for construction of C─N axially chiral indoles and pyrroles

“…As depicted in Fig. 4 , ynamines bearing different allyl ethers were appropriate with this reaction for highly enantioselective preparation of C─N axially chiral indoles 57 to 59 in 54 to 90% yields and 92 to 94% ees with excellent chemoselectivity without the observation of any central chiral products ( 59 – 61 ). Moreover, the chiral indole 60 from geraniol linked with two double bonds, which could not affect this asymmetric [2+2+2] cycloaddition, was obtained with excellent yield and enantioselectivity.…”

Valence-isomer selective cycloaddition reaction of cycloheptatrienes-norcaradienes

“…Consequently, the combination of a three hidden-layer Neural Network 58,59 and a 4096-bit Avalon fingerprint yielded a high coefficient of determination (detailed heat maps and correlation plots are available, Supplementary Figs. [5][6][7][8][9][10][11]. Subsequently, we selected 80 compounds in the chemical information database (SciFinder n ) and tested them using the created algorithm (Supplementary Software 1, Fig.…”

“…Antiviral Oseltamivir has also been synthesized by a stereoselective Diels-Alder reaction 5 for constructing functionalized core carbocycles 6,7 . Control of the site-8 , regio- 9,10 ; and stereoselectivities 11,12 in intermolecular cycloadditions using structurally unsymmetrical reactants, however, remains challenging even in modern organic chemistry 13,14 . Cycloheptatriene (CHT) and norcaradiene (NCD) exist in a unique state of equilibrium as valence isomers, giving rise to a diverse range of reaction manifolds that lead to an array of similar, yet distinct, cycloadducts (Fig.…”