{'fraction_non_alphanumeric': 0.05216197666437886, 'fraction_numerical': 0.026767330130404943, 'mean_word_length': 5.126050420168068, '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}}
Copper(I)‐mediated 1,2‐ and 1,4‐Reductions

Long before Kharasch’s seminal paper on copper-catalyzed additions of Grignard reagents to conjugated enones (1941) [1] and Gilman’s first report on formation of a lithiocuprate (Me2CuLi; 1952) [2] appeared, Cu(I) hydride had been characterized by Wurtz as a red-brown solid [3]. Thus, ‘‘CuH’’ is among the oldest metal hydrides to have been properly documented, dating back to 1844. Although studied sporadically for many decades since, including an early X-ray determination [4], most of the initial ‘press’ on copper hydride was not suggestive of it having potential as a reagent in organic synthesis. In fact, it was Whitesides who demonstrated that this unstable material is often an unfortunate result of a b-elimination, which occurs to varying degrees as a thermal decomposition pathway of alkylcopper species bearing an available b-hydrogen (such as n-BuCu; Eq. 5.1) [5]. Stabilized forms of CuH, most notably Osborn’s hexameric [(Ph3P)CuH]6 [6], for which an X-ray structure appeared in 1972, for years saw virtually no usage in organic synthesis even in a stoichiometric sense, let alone a catalytic one. Several groups in the 1970s and early 80s, however, recognized the value of hydride delivery to a; b-unsaturated frameworks with the aid of copper complexes. This interest resulted in several hydrido cuprates of widely varying constitution, each intended for use as a stoichiometric 1,4-reductant.