Efficient Nazarov Cyclizations of 2-Alkoxy-1,4-pentadien-3-ones
摘要:
[GRAPHICS]Expeditious and high-yielding Nazarov cyclizations of 2-alkoxy-1,4-pentadien-3-ones are described. An example of a catalytic asymmetric Nazarov cyclization is presented.
New Synthetic Approach to Cyclopenta-Fused Heterocycles Based upon a Mild Nazarov Reaction
作者:Ernesto G. Occhiato、Cristina Prandi、Alessandro Ferrali、Antonio Guarna、Paolo Venturello
DOI:10.1021/jo034939p
日期:2003.12.1
role in forcing the conrotatory process to take place in one sense only: allowing the synthesis of diastereomerically pure compounds to be realized. Because different patterns of substitution on the heterocycle are compatible with the reaction conditions, the methodology developed could be very useful for the synthesis of natural products and biologically active compounds containing cyclopenta-fused O-
A chiral variant of B(C6F5)3 with a 3,3′‐disubstituted binaphthyl backbone is shown to catalyze Nazarov cyclizations with high levels of enantio‐ and diastereocontrol. The parent B(C6F5)3 also promotes these ring closures efficiently. This electrocyclization is another example of the still small family of C−C bond formations mediated by B(C6F5)3 as the catalyst.
具有3,3'-双取代的联萘骨架的B(C 6 F 5)3的手性变异体可催化Nazarov环化反应,并具有高水平的对映和非对映控制。母体B(C 6 F 5)3也有效地促进了这些环的闭合。这种电环化是由B(C 6 F 5)3作为催化剂介导的C-C键形成家族仍然很小的另一个例子。
Natural deep eutectic solvents as an efficient and reusable active system for the Nazarov cyclization
Natural deep eutectic solvents have emerged as alternative non-toxic, non-aqueous solvents for an increasing number of synthetic transformations. Remarkably, in some cases one (or more) components of the NaDES plays an active role in the reaction mechanism and directly participates as either a catalyst or a reagent in the reaction. In this paper, we tested several NaDESs in which one of the components
A novel catalyst system—a combination of the readily available 2,2′-biphenol with the inexpensive, nontoxic, and eco-friendly B(OH)3—promoted the Nazarov cyclization of activated and inactivated divinyl ketones to afford the corresponding cyclopentenones up to 96% yield under, in a cis-selective manner. Compared with the conventional harsh conditions with hazardous reagents, user-friendly method was established with bench-stable and easy-to-handle reagents.
Iodolium salts as halogen-bond donor catalysts in the Nazarov cyclization: the molecular oxygen enigma
作者:Avery J. To、Graham K. Murphy
DOI:10.1039/d2nj02731c
日期:——
Nazarov cyclizations of activated precurosrs are achieved under iodolium catalysis, provided that oxygen is present for catalyst activation and turnover.