Synthesis of an austrodorane sesquiterpenoid core via a transannular Prins cyclization

The bicyclo[4.3.0]nonane core of the austrodorane family of sesquiterpenoids has been synthesized via a novel transannular Prins cyclization. This strategy formed the fused 5,6-ring system and installed the required quaternary stereocentre at the ring fusion in a single step.     

Stereochemical Prins cyclization: electronic versus steric effects on the synthesis of 2,4,6-trisubstituted tetrahydropyran rings

A convenient approach towards the synthesis of both syn- and anti-2,4,6-chlorotetrahydropyrans has been developed. The electronic and steric influences on the stereochemistry of the Prins cyclized products were investigated based on the substituents of the homoallylic alcohol.     

An Efficient Prins Cyclization for Stereoselective Synthesis of Tetrahydropyran from Imines and Homoallyl Alcohols

An unprecedented protocol has been developed for the efficient synthesis of substituted tetrahydropyrans via a bismuth‐promoted Prins cyclization of imines with homoallyl alcohols. In the presence of 40 mol% BiCl₃, a wide variety of imines react smoothly with homoallyl alcohols at room temperature to give the corresponding 4‐chlorotetrahydropyran derivatives in good to excellent yields.     

Stereoselective Total Synthesis of Botryolide E and Ophiocerin C

A highly stereoselective approach to the total synthesis of the γ‐lactone derivative botryolide E and tetrahydropyran derivative ophiocerin C via a common polyketide precursor by means of Prins cyclization and MacMillan α‐aminoxylation sequence is described. The method can conveniently be utilized for the preparation of further related γ‐lactone and tetrahydropyran derivatives.     

Highly Efficient Synthesis of 1,3-Dioxanes via Prins Reaction in Brønsted-Acidic Imidazolium Ionic Liquid

The high-yielding synthesis of a wide variety of 1,3-dioxanes via the Prins reaction under mild conditions has been demonstrated using Brønsted-acidic imidazolium ionic liquid [bmim(SO₃H)][OTf] or bmimOTf. The use of ionic liquid makes this synthesis simple, convenient, cost-effective, and environmentally friendly. Furthermore, bmimOTf was conveniently separated from the products and can be easily recycled for the Prins reaction with excellent yields. This method works well with a variety of aliphatic aldehydes including formaldehyde, acetaldehyde, propionaldehyde, and cyclohexanecarboxaldehyde.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

酸功能化离子液体催化三聚甲醛与烯烃的Prins反应

以烯烃和三聚甲醛为原料,采用酸功能化离子液体作催化剂,在无溶剂体系中经Prins反应合成了1,3-二氧己环衍生物.对不同离子液体的催化活性进行了考察,选择[BsTmG][HSO4]作为反应的催化剂.研究了温度、时间以及原料摩尔比对反应的影响,得到较佳实验条件为:催化剂用量为烯烃摩尔量的5%,三聚甲醛与烯烃摩尔比为1∶1,温度80℃,时间10 h.该催化体系具有较好的底物适用性,离子液体[BsTmG][HSO4]经简单的萃取分离后重复使用8次,仍保持较好的催化活性.     

N-Methylanilinium trifluoroacetate-promoted Prins reaction of α-methylene-α-tetralone dimers: generation of new molecular scaffolds

α-Methylene-α-tetralone dimers (8-10) are shown to undergo a diastereoselective Prins reaction with paraformaldehyde in the presence of N-methylanilinium trifluoroacetate resulting in 2, 4, and 5. The structure of the new scaffold 2 was confirmed by X-ray crystallographic analysis.