通过一锅S N 2'烯丙基化-Wittig策略从磷鎓叶立德,烯丙基碳酸酯和醛中无催化剂地合成烷基二烯
摘要:
提出了通过区域选择性的S N 2'方法将稳定的磷化磷与烯丙基碳酸酯进行无催化剂的烯丙基烷基化反应。随后的与脂肪族和芳香族醛以及乙烯酮的一锅Wittig反应可提供结构多样的跳跃式二烯(1,4-二烯),且产率高,并且具有灵活的取代基图案,具有中等至出色的立体选择性。这种单锅S N 2'烯丙基化-维蒂希(Wittig)策略构成了一种方便有效的合成方法,用于从容易获得的起始原料中高度官能化的二烯。
The coupling of α,β-unsaturated carbonyl compounds with aldehydes (the Baylis-Hillman reaction) was accelerated in the presence of a catalytic amount of 1,4-diazabicyclo[2,2,2]octane (DABCO) and lithium perchlorate in ether. A preliminary kinetic study revealed that the relative rate of the reaction using LiClO4 in ether was 8.0×102 times faster than that of the reaction without LiClO4.
Ultrasound in Baylis–Hillman reactions with aliphatic and aromatic aldehydes: scope and limitations
作者:Fernando Coelho、Wanda P. Almeida、Demetrius Veronese、Cristiano R. Mateus、Elizandra C. Silva Lopes、Rodrigo C. Rossi、Gabriel P.C. Silveira、César H. Pavam
DOI:10.1016/s0040-4020(02)00822-0
日期:2002.9
The utilization of ultrasound radiation in the Baylis–Hillman reaction with several aldehydes (aromatics and aliphatics) and different α,β-unsaturated reactants is described. For all aldehydes tested, the utilization of ultrasound sources augmented the reactionrate and the chemical yields. The use of ultrasound with two different catalysts (tri-n-butylphosphine and 1,4-diazabicyclo[2.2.2]octane [DABCO])
Multifunctional chiral phosphines-catalyzed highly diastereoselective and enantioselective substitution of Morita–Baylis–Hillman adducts with oxazolones
作者:Yuan-Liang Yang、Cheng-Kui Pei、Min Shi
DOI:10.1039/c1ob00017a
日期:——
Multifunctional chiral phosphine (phosphine–thiourea type) L2-catalyzed allylicsubstitutions of MBH adducts 1 with oxazolones 2 produce the corresponding optically active adducts 3 in good to excellent yields and ee's as well as moderate to good de's under mild conditions. The synergistic interaction between hydrogen bond donor site and nucleophilic site has been discussed, indicating that finely
Efficient and general conditions for the formation of stereodefined trisubstituted alkenes by using the rhodium‐catalyzed reaction of unactivated Baylis–Hillman adducts with either organoboronic acids or potassiumtrifluoro(organo)borates are reported (see scheme).