Synthesis of Stereopentad Analogues of the C14−C22 Segment of Callystatin A through Additions of Chiral Allenylzinc Reagents to Stereotriads
作者:James A. Marshall、Gregory M. Schaaf
DOI:10.1021/jo015936k
日期:2001.11.1
The addition of (P)- and (M)-allenylzinc reagents, prepared in situ through Pd-catalyzed metalation of (R)- and (S)-3-butyn-2-ol mesylates, to diastereomeric stereotriad aldehydes 8, 13, 18, and 23 of syn,syn, syn,anti, anti,anti, and anti,syn stereochemistry was examined. Additions to the former two aldehydes afforded the four anti adducts with high diastereoselectivity and negligible mismatching
通过(R)-和(S)-3-butyn-2-ol甲磺酸酯的Pd催化金属化原位制备的(P)-和(M)-烯丙基锌试剂添加到非对映体立体三单元醛8,13,检查了syn,syn,syn,anti,anti,anti和anti,syn立体化学的18和23。除前两种醛外,这四种反加合物的非对映选择性高,错配可忽略不计。在后两种醛和(M)-烯基锌试剂中观察到明显的错配。考虑到空间和偶极控制元件,提出了可能的过渡态的评估。