{'fraction_non_alphanumeric': 0.03668261562998405, 'fraction_numerical': 0.009569377990430622, 'mean_word_length': 5.752688172043011, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Organocatalytic asymmetric conjugate addition of cyclic 1,3-dicarbonyl compounds to β,γ-unsaturated α-ketoesters

The conjugate addition of cyclic 1,3-dicarbonyl compounds to β,γ-unsaturated α-keto-esters was studied using a series of chiral bifunctional organocatalysts. Takemoto’s catalyst was found to be most efficient for this transformation. Excellent yields and good enantioselectivities were achieved for a variety of β,γ-unsaturated α-keto-esters and cyclic 1,3-dicarbonyl compounds. A bifunctional catalytic mechanism is proposed. The method provides a new asymmetric synthetic route for chiral courmarin derivatives.