Highly Selective Palladium Catalyzed Kinetic Resolution and Enantioselective Substitution of Racemic Allylic Carbonates with Sulfur Nucleophiles: Asymmetric Synthesis of Allylic Sulfides, Allylic Sulfones, and Allylic Alcohols
作者:Hans-Joachim Gais、Thomas Jagusch、Nicole Spalthoff、Frank Gerhards、Michael Frank、Gerhard Raabe
DOI:10.1002/chem.200204657
日期:2003.9.5
enantioselectivity of the substitution step is, under the conditions used, independent of the chirality of the substrate; this shows that no "memory effect" is operating in this case. Hydrolysis of the carbonates ent-1 a-c, ent-3 aa and ent-3 ba, which were obtained through kinetic resolution, afforded the enantiomerically highly enriched cyclic allylic alcohols 9 a-c (>/=99 % ee) and acyclic allylic alcohols 10
我们描述了高选择性钯催化的消旋环状烯丙基碳酸酯rac-1 ac和消旋非环状烯丙基碳酸酯rac-3aa和rac-3 ba通过与叔丁基亚磺酸盐,甲苯基亚磺酸盐,苯基亚磺酸盐阴离子和2-嘧啶硫醇反应而得到的动力学拆分。 N,N′-(1R,2R)-1,2-环己烷二基双[2-(二苯基膦基)-苯甲酰胺](BPA)作为配体。选择性以回收的底物和产物的收率和ee值以及选择性因子S表示。在BPA存在下,碳酸环己烯酯1 a(> / = 99%ee)与2-嘧啶硫醇的反应显示出在所使用的条件下,相对于烯丙基底物的总体拟零级动力学。还描述了环状和非环状烯丙基叔丁基砜2aa,2b,2c,2d和4ac以及环状和非环状烯丙基2-嘧啶基-2-的高选择性钯催化的不对称合成。在BPA存在下,分别从相应的外消旋碳酸根,亚磺酸根阴离子和硫醇分别得到吡啶基-和4-氯苯基硫化物5aa,5b,5ab,6aa-ac,6ba和6bb。E-构