Asymmetric induction in the addition of chiral carbalkoxycarbenoids to styrene

Semicorrin metal complexes as enantioselective catalysts. Part 2. Enantioselective cyclopropane formation from olefins with diazo compounds catalyzed by chiral (semicorrinato)copper complexes

“…The configuration of the menthyl group had a distinct effect on the enantioselectivity of the reaction. Although such an effect is negligible in the cyclopropane foirmation with achiral Cu catalysts [8], the interaction between the chiral menthyl group and the chiral semicorrin catalyst results in a marked selectivity difference between (1 S,3S,4R)-and (1 R,3R,4S)-menthyl diazoacetate. Analogous findings have been reported for cyclopropane formations with the catalyst 3 [4].…”

“…-As a first test of the semicorrin ligands 1, we have investigated the properties of the Cu complexes 5- 8 as catalysts for the cyclopropane formation from styrene with alkyl diazoacetates, a reaction which has been I CN widely used as a standard for assessing the efficiency and selectivity of catalysts in cyclopropane formation [4-61. The preparation and structural features of the complexes [5][6][7][8] have been discussed in the preceding communication [2]. All four complexes were found to be efficient catalysts, converting styrene and ethyl diazoacetate to optically active 2-phenylcyclopropane-1-carboxylates 9a and 9b in 60-80 % yield (cf.…”

“…Eschenmoser for his support, Dr. Dorothee Felix for her advice and assistance with the GC analyses, and Daniel Muller (Diplomarbeit ETH-2, 1985) for preliminary experiments. [4] [8]). -(1 S,3S,4R)-Menthyl Chloroacetare ( = ( I S,2 R,5 S J-2-Isopropyl-5-methylcyclohexyl Chloroacetate).…”

Enantioselective Catalysis with Chiral Cobalt and Copper Complexes

“…Cyclopropanation of Styrene with Menthyl Diazoacetate. In a two-necked flask fitted with a rubber septum, a bubbler, and a magnetic stirrer, 10 drops of a solution of (+ )-menthyl diazoacetate [23,28,29,41) (2.24 gIl 0 mmol in 3 ml of 1,2-dichloroethane) were added to a mixture of the bis(semicorrinato) complex 14 (64 mg, 0.1 mmol), 5 ml of 1,2-dichloroethane, and 2.3 ml (20 mmol) of styrene under N2. The flask was heated in an oil bath to 85° (ca.…”

Synthesis, Properties, and Doping Behavior of Optically Active Polythiophenes Bearing a Bornyl Group

“…l ‐Borneol is an inexpensive terpenoid colorless crystal. l ‐Borneol itself attracts much attention for pharmaceutics and fragrances . In view of its chemical structure, the bornyl group has spherical with three chiral centers.…”