Several additives were screened for the stereoselective reduction of a 4-substituted cyclohexanone en route to linrodostat mesylate. It was found that the addition of sub-stoichiometric cerium(III) chloride in conjunction with sodium borohydride provided the desired trans-cyclohexanol (arising out of axial delivery of the hydride onto the carbonyl) in >16:1 selectivity and excellent conversion. The reaction was initially scaled up to 3.5 kg scale and eventually to >100 kg scale.

中文翻译：

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氯化铈（III）介导的NaBH ₄取代4取代的环己酮的立体选择性还原

筛选了几种添加剂，以选择性地将4-取代的环己酮立体选择性地还原为甲磺酸林洛司他。发现亚化学计量的氯化铈（III）与硼氢化钠的结合提供了所需的反式环己醇（由于氢化物轴向输送到羰基上）而具有> 16：1的选择性和出色的转化率。最初将反应规模扩大至3.5千克规模，最终扩大至> 100千克规模。