{'fraction_non_alphanumeric': 0.02806824435883324, 'fraction_numerical': 0.007705008255365988, 'mean_word_length': 5.204778156996587, '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}}
On water and in air: fast and highly chemoselective transfer hydrogenation of aldehydes with iridium catalysts.

The use of water as a solvent for organic reactions has emerged as one of the most interesting fields for organic chemists, both in the laboratory and in industry, because of substantial economical and ecological gains. Recently, Sharpless and co-workers demonstrated the benefits of performing C C bond-formation reactions “on water”. We recently discovered that water is an excellent solvent for the asymmetric transfer hydrogenation of ketones. Herein, we disclose that [(Cp*IrCl2)2] (Cp*=C5Me5) in combination with monotosylated ethylenediamine is a good catalyst system for highly chemoselective transfer hydrogenation (TH) of aldehydes. The reduction works in air and appears to occur on water. TH reactions have been studied for more than one century. The reduction of ketones and aldehydes by the Meerwein–Ponndorf–Verley reaction was first described in 1925, and since then a great deal of progress has been made in TH chemistry. However, aldehydes are difficult to reduce by catalysts commonly used for TH, and controlling the chemoselectivity of the reaction presents a further challenge. To date, the most efficient TH catalyst appears to be the iridium complex of an N-heterocyclic carbene, which affords a turnover frequency (TOF) of up to 3000 h 1 in refluxing 2-propanol. With most other metal catalysts, the TOFs range from a few to several hundred per hour. In fact, few catalysts have been reported that enable fast, selective, and productive TH of aldehydes with inexpensive, eco-friendly reductants, and that can tolerate the presence of synthetically useful functional groups. In continuing our investigation into aqueous TH reactions, we examined the TH of benzaldehyde with HCOONa