School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, India.
J Org Chem. 2022 May 20;87(10):6695-6709. doi: 10.1021/acs.joc.2c00374. Epub 2022 May 6.
Development of simple synthetic methods from readily available compounds to complex products is of utmost interest in modern synthesis. Catalytic synthesis of cyclopropanes is important for diverse chemical applications. We present a method for the transformation of readily accessible α,β-unsaturated ketones (chalcones) to cyclopropanes. A simple base, KOH, catalyzed the selective reduction of the enone carbonyl functionality, dehydrogenative silylation, and deoxygenative cyclization of chalcones to provide the cyclopropane products. Chalcones with extended conjugation and 4-chromanone-based substrates also provided the corresponding cyclopropanes. One-pot synthesis of cyclopropanes directly from industrial feedstock compounds such as ketones and aldehydes is also demonstrated using catalytic KOH for both intermolecular condensation and dehydrogenative silylation-deoxygenative intramolecular cyclization cascade.
从易得的化合物发展简单的合成方法以得到复杂产物在现代合成中至关重要。环丙烷的催化合成对于多种化学应用很重要。我们提出了一种将易得的α,β-不饱和酮（查耳酮）转化为环丙烷的方法。一种简单的碱 KOH 可以催化烯酮羰基官能团的选择性还原、脱氢硅化以及查尔酮的脱氧环化，从而得到环丙烷产物。具有扩展共轭的查尔酮和基于 4-色满酮的底物也提供了相应的环丙烷。通过使用 KOH 催化的分子间缩合和脱氢硅化-脱氧分子内环化级联反应，也可以直接从工业原料化合物如酮和醛一锅法合成环丙烷。
