Chiral Induction in [2+2+2] Cycloaddition Reactions

Abstract

Chiral compounds containing six-membered rings, whether aromatic or not, are of interesti nawide range of disciplines, including materials cience, medicinal chemistry, and agrochemistry.A st ransition-metal-catalyzed[ 2 + +2+ +2] cycloaddition reactions are one of the most elegant routes for the construction of six-memberedr ings, significant effort has been given to developing asymmetric variants.I nt his focus review, we bring together the work that has been done in optimizing diastereoselective [2+ +2+ +2] cycloaddition reactions of enantiomerically pure substrates. Twod ifferent approaches-chirality inductiona nd chirality transfer-are considered in ar eview organized by the typeo fc hiral element being constructed (central, axial, or helical). The general challenges that are involved are highlighted and possible future directions in the field are discussed.The ORCID identification number(s) for the author (s) of this articlecan be found under: https://doi.org/10.1002/ajoc.201800291. Scheme1.Transition-metal-catalyzed [2+ +2+ +2] cycloadditions of three alkynes. Scheme2.Postulated generalmechanism of [2+ +2+ +2] cycloaddition reaction of three alkynes,w here M = transition-metal catalyst. Scheme3.Co-mediated [2+ +2+ +2] cycloadditions of enediynes containing cyclic chiralp hosphine oxides. Scheme14. Co-mediated [2+ +2+ +2] cycloadditions of enantiopuretriynes 72-78 to afford non-racemic helicene-like derivatives 79-85. Scheme15. Co-mediated [2+ +2+ +2] cycloadditions of enantiopuretriynes 86-87 to afford non-racemic [6] and [7]helicene-like derivatives. Scheme16. Co-catalyzed [2+ +2+ +2] cycloadditions of enantiopure triynes 90-92 to affordnon-racemic [5] and [6]helicene-like derivatives.

A Rh(I)‐Catalyzed Cascade Cyclization of 1,5‐Bisallenes and Alkynes for the Formation of cis‐3,4‐Arylvinyl Pyrrolidines and Cyclopentanes

“…Furthermore, in rhodium-catalyzed cycloaddition reactions it is known that alkynes are much more reactive than alkenes, and that the reactivity of allenes falls somewhere between the two. [37][38][39] Thus, as a continuation of our programme based on the development of rhodium-catalysed cycloadditions involving allenes, [35][36][37][38][40][41][42] we asked ourselves what the favoured reaction pathway would be if we treated 1,5-bisallenes with alkynes under rhodium catalysis. We reasoned that the greater reactivity of alkynes as compared to alkenes might favour a fully rhodium catalysed cascade process.…”

The Choice of Rhodium Catalysts in [2+2+2] Cycloaddition Reaction: A Personal Account

“…The chirality of the starting bisallene substrate can be completely transferred to the cycloadduct, representing an atomeconomical and enantiospecific process for the construction of fused funcionalized polycycles (Scheme 10). This study prompted us to write a review article based on the diastereose-lective [2+2+2] cycloaddition reactions of enantiomerically pure substrates considering two different approaches: chirality induction and chirality transfer [34]. Due to the versatility we found in the use of rhodium-catalyzed cycloaddition reactions involving allenes, we were interested in studying [2+2+2] cycloaddition reactions using substrates with three different unsaturations: an allene, an alkene, and an alkyne.…”

Research Progress on the Syntheses of Chiral Methyl-Branched Aliphatic Hydrocarbons Insect Pheromones

“…他 们以溴化三苯基(R)-(2-甲基-3-羟基丙基)鏻( 7 [40] . Perlmutter 等 [36] 以(R)-3-甲基-4-丁内酯( 14 [41][42] . 在单手性甲基脂肪烃类昆虫性信 息素的合成研究中, 常用的手性诱导试剂有(-)-莰烷磺 内酰胺 [43] 、(S)-1-氨基-2-甲氧甲基吡咯烷 [44] 、(S)-4-苄 基-2-噁唑烷酮 [45] 、(S)-4-异丙基-2-噁唑烷酮 [46] 等.…”