Phosphine-Catalyzed Synthesis of 1,3-Dioxan-4-ylidenes
摘要:
A phosphine-catalyzed reaction of an allenoate with aldehydes furnished (2,6-diaryl-[1,3]dioxan-4-ylidene)-acetates 4 in excellent to moderate yields with complete diastereoselectivity and high E/Z-selectivities. Upon removal of the acetal functionality in this domino reaction product 4, delta-hydroxy-beta-ketoester 11 was obtained. The reported vinylphosphonium-based approach provides a new way to achieve a synthesis of 6-hydroxy-beta-ketoesters that differs from the classical dianion-based approach.
作者:Kui Zhang、Lingchao Cai、Zhongyue Yang、K. N. Houk、Ohyun Kwon
DOI:10.1039/c7sc04381c
日期:——
A novel bridged [2.2.1] bicyclic phosphineoxide, devised to circumvent the waste generation and burdens of purification that are typical of reactions driven by the generation of phosphineoxides, has been prepared in three steps from commercially available cyclopent-3-ene-1-carboxylic acid. The performance of this novel phosphineoxide was superior to those of current best-in-class counterparts, as