{'fraction_non_alphanumeric': 0.047244094488188976, 'fraction_numerical': 0.0026246719160104987, 'mean_word_length': 5.9363636363636365, '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}}
Discrimination of diazo compounds toward carbenoids: copper(I)-catalyzed synthesis of substituted cyclobutenes.

In the last few years the role of diazo compounds in organic synthesis, particularly in cyclization reactions via metal carbenoids (metal: ruthenium, copper, rhodium, etc.) has been prominent. By taking advantage of the ease with which these metal carbenes collapse into the corresponding symmetrical alkenes (homocoupling), we and others have been able to access nonsymmetrical alkenes by the selective heterocoupling of diazoacetate esters with copper(I) and ruthenium(II) carbene complexes [Eq. (1)]. Interestingly, the metal-catalyzed selective cross-coupling reaction between two different diazo substrates has been reported recently [Eq. (2)].