作者:Rudolf Knorr、Eva Rossmann、Monika Knittl
DOI:10.1055/s-0029-1218797
日期:2010.7
turn yields xyl*-CO2H (63%). The corresponding 4-methyl-derivatives of these compounds were obtained analogously. The acid chloride xyl*-COCl (77% yield) acylates HalMgCH2R to give only xyl*-COCH3 (86%) or xyl*-COEt (97%). These two ketones react with n-butyllithium (no carbonyl addition) and Cl-PO(OEt)2 to furnish only the enol phosphates xyl*-C(=CH2)OPO(OEt)2 (84%) or xyl*-C(=CHCH3)OPO(OEt)2 (up to 70%)
尽管通过2,6-二叔丁基苯基('super-2,6-xylyl'= xyl *)进行空间屏蔽,但廉价的酚钠(xyl * -ONa)与硫酸二甲酯反应仅生成xyl * -OCH 3(94%),完全抑制了替代的4-甲基化。通过元素锂在电子载体的帮助下对xyl * -OCH 3的还原裂解生成xyl * -Li,这又产生了xyl * -CO 2 H(63%)。这些化合物的相应的4-甲基衍生物类似地获得。酰氯xyl * -COCl(收率77%)酰化HalMgCH 2 R,仅得到xyl * -COCH 3(86%)或xyl * -COEt(97%)。这两个酮与n反应-丁基锂(无羰基加成)和Cl-PO(OEt)2仅提供烯醇磷酸盐xyl * -C(= CH 2)OPO(OEt)2(84%)或xyl * -C(= CHCH 3)OPO (OEt)2(最高70%)。当后两种产物用叔丁基锂处理时,仅发生1,2-消