Bridging the Final Gap in Stereocontrolled Wittig Reactions: Methoxymethoxy-Armed Allylic Phosphorus Ylides Affording Conjugated Dienes with Highcis Selectivity
sodium amide), 2-alkenyltris(2-methoxymethoxyphenyl)phosphonium salts carrying an allyl, crotyl, or prenyl (3-methyl-2-butenyl) side chain condense with saturated or unsaturated aldehydes to give conjugated dienes with Z/E ratios ranging from 90:10 to > 99:1 and averaging 96:4. Owing to steric congestion, yields are only moderate (on average 41%; extremes 10-79%). The nonvolatile tris(2-methoxymethoxyphenyl)phosphine
Stereoselective synthesis of substituted 1,3,5-hexatrienes from diallylic sulfones
作者:Xiao-Ping Cao、Tze-Lock Chan、Hak-Fun Chow、Jingren Tu
DOI:10.1039/c39950001297
日期:——
Substituted 1,3,5-hexatrienes 7 can be prepared in excellent yields and with good stereoselectivity from diallylic sulfones 6 employing a modified Ramberg–Bäcklund reaction.
Coxon,J.M. et al., Australian Journal of Chemistry, 1971, vol. 24, p. 1481 - 1486
作者:Coxon,J.M. et al.
DOI:——
日期:——
<i>Z</i>-Selective Metathesis Homocoupling of 1,3-Dienes by Molybdenum and Tungsten Monoaryloxide Pyrrolide (MAP) Complexes
作者:Erik M. Townsend、Richard R. Schrock、Amir H. Hoveyda
DOI:10.1021/ja303220j
日期:2012.7.18
Molybdenum or tungsten monoaryloxide pyrrolide (MAP) complexes that contain OHIPT as the aryloxide (hexaisopropylterphenoxide) are effective catalysts for homocoupling of simple (E)-1,3-dienes to give (E,Z,E)-trienes in high yield and with high Z selectivities. A vinylalkylidene MAP species was shown to have the expected syn structure in an X-ray study. MAP catalysts that contain OHMT (hexamethylterphenoxide)
包含 OHIPT 作为芳基氧化物(六异丙基三苯醚)的钼或钨单芳基氧化物吡咯化物 (MAP) 配合物是简单 (E)-1,3-二烯均偶联以高产率得到 (E,Z,E)-三烯的有效催化剂高 Z 选择性。在 X 射线研究中显示出乙烯基亚烷基 MAP 物质具有预期的顺式结构。含有 OHMT(六甲基三苯醚)的 MAP 催化剂效率相对较低。