Enantioselective Cobalt‐Catalyzed [6+2] Cycloadditions of Cycloheptatriene with Alkynes

Abstract

Abstract The enantioselective cobalt‐catalyzed [6+2] cycloadditions of cycloheptatriene 1 with alkynes 2 is reported. Chiral phosphoramidites based on 3,3′‐disubstituted ( R )‐BINOL appeared to be efficient ligands, affording the corresponding cycloadducts with good yields and up to 92 % ee . A vibrational circular dichroism study afforded the absolute configuration of new chiral (+)‐(1 S ,6 R )‐7‐phenyl[4.2.1]bicyclo‐ nonatriene 3a and (−)‐(1 S ,6 R )‐7‐trimethylsilyl[4.2.1]bicyclononatriene 3c .