Applications of the Chiral Auxiliaries DIOZ and TRIOZ for Conjugate Additions and Comparison with Other Auxiliaries
作者:Hanspeter Sprecher、Stefan Pletscher、Manuel Möri、Roger Marti、Christoph Gaul、Krystyna Patora-Komisarska、Ekatarina Otchertianova、Albert K. Beck、Dieter Seebach
DOI:10.1002/hlca.200900385
日期:2010.1
prepared and used for conjugate additions of organocuprate reagents (Me, iPr, Ph, 4‐MeOPh) in the β‐carbonyl (Table 2) and in the α‐carbonyl position (NO2‐derivative 11 in Scheme 3). The yields and diastereoselectivities are compared with previously tested enoyl‐oxazolidinones (Table 2). Highest diastereoselectivities (>90%) are always observed with the 4‐Ph derivatives (Hruby effect). Nitroacryloyl‐oxazolidinones
许多ñ -丙烯酰基,Ñ -crotonoyl-,ñ - (3,3,3- trifluorocrotonoyl) - ,Ñ -cinnamoyl-,和ñ - (3- nitroacryloyl)-4-异丙基或-4-苯基唑烷-2-酮与偕二苯基取代,即,7 - 15,已被制备并用于有机铜试剂的共轭加成(Me中,我PR,pH值,4-MeOPh)在β -羰基(表2),并在的α -羰基位置(NO 2 -衍生物11在方案3中)。将产率和非对映选择性与先前测试的烯酰基-恶唑烷酮(表2)进行比较。使用4-Ph衍生物总是观察到最高的非对映选择性(> 90%)(Hruby效应)。硝基丙烯酰基-恶唑烷酮和相应的苯薄荷醇酯的非对映选择性加成较少(方案3)。还测试了由3-(1-甲基乙基)-5,5-二苯基恶唑烷二-2-酮(DIOZ)衍生的Li 2-烯酸酯-亚硝酸盐的α-羰基烷基化反应(方案4)。描述了三种丙烯酰基-恶唑