Organocatalytic Michael addition–lactonisation of carboxylic acids using α,β-unsaturated trichloromethyl ketones as α,β-unsaturated ester equivalents
作者:Louis C. Morrill、Daniel G. Stark、James E. Taylor、Siobhan R. Smith、James A. Squires、Agathe C. A. D'Hollander、Carmen Simal、Peter Shapland、Timothy J. C. O'Riordan、Andrew D. Smith
DOI:10.1039/c4ob01788a
日期:——
Isothiourea HBTM-2.1 catalyses the Michael addition–lactonisation of 2-aryl and 2-alkenylacetic acids and α,β-unsaturated trichloromethyl ketones. Ring-opening of the resulting dihydropyranones and subsequent alcoholysis of the CCl3 ketone with an excess of methanol gives a range of diesters in high diastereo- and enantioselectivity (up to 95 : 5 dr and >99% ee). Sequential addition of two different
异硫脲 HBTM-2.1 催化 2-芳基和 2-烯基乙酸和 α,β-不饱和三氯甲基酮的迈克尔加成-内酯化。所得二氢吡喃酮的开环和随后用过量甲醇对 CCl 3酮进行醇解得到一系列具有高非对映和对映选择性的二酯(高达 95 : 5 dr 和 >99% ee)。将两种不同的亲核试剂依次添加到二氢吡喃酮上,得到相应的不同取代的二酸衍生物。