A concise and practical stereoselective synthesis of ipragliflozin L-proline

• Shuai Ma,
• Zhenren Liu,
• Jing Pan,
• Shunli Zhang and
• Weicheng Zhou

Beilstein J. Org. Chem. 2017, 13, 1064–1070, doi:10.3762/bjoc.13.105

• yield was 52% in three steps and the product purity was excellent. Two key diastereomers were prepared with efficient and direct access to the α-C-arylglucoside. Keywords: arylzinc derivative; β-C-arylglucoside; diastereomer impurity; ipragliflozin L-proline; stereoselective synthesis; Introduction

• –zinc exchange and transmetalation to produce the arylzinc derivative in situ in this reaction. However, further increasing the amount of zinc bromide to 1.0 equiv did not improve the reaction (Table 1, entry 5) and elevation of the reaction temperature to −10 °C (Table 1, entry 6) worsened the reaction

• the literature reported [19], and the structure was confirmed by MS and NMR. The α-anomers of 5 and 6 were the key impurities during the synthetic process. Pure compounds of 5’ and 6’ were prepared for the analytical references (Scheme 4). Compound 4a was converted to the corresponding arylzinc

Stereoselective synthesis of tetrasubstituted alkenes via a sequential carbocupration and a new sulfur–lithium exchange

• Andreas Unsinn,
• Cora Dunst and
• Paul Knochel

Beilstein J. Org. Chem. 2012, 8, 2202–2206, doi:10.3762/bjoc.8.248

• 9 in 77% yield. Direct Pd-catalyzed Negishi cross-coupling [24][25][26][27][28] of 9 with an arylzinc derivative failed. However, the bromide 9 could be readily converted to the corresponding iodide 10 by a bromine–magnesium exchange using iPrMgCl·LiCl [29][30][31][32][33][34][35] followed by