This Personal Account summarizes our recent efforts in searching for novel synthetic strategies for a number of organic molecules by using allene derivatives as valuable substrates. It starts with a concise description of the background of allene-related synthetic chemistry. The second part deals with the reactions of 1,2-allenic ketones, including the reactions of 1,2-allenic ketones with various nucleophiles to afford functionalized benzenes, heterocycles, and fluoroenones, and those of allenic ketones as nucleophiles under the promotion of bases to provide 1,3,4′-triones or functionalized furans. The third part of this account focuses on the reactions of α-allenic alcohols. In this section, multicomponent reactions involving α-allenic alcohols, and cascade reactions of α-allenic alcohols promoted by Brønsted acid or iodine, are presented.

In this paper, a selective and versatile synthesis of functionalized phenols including 2-hydroxyaryl ketones through cascade reactions of 1,2-allenic ketones with β-diketones has been developed. The synthetic procedure is not only efficient, but also easy to handle and compatible with a variety of functional groups. In addition, reactions were combined with a subsequent condensation of the in-situ-formed o-hydroxyaryl ketones with an α-bromoketone, thus resulting in a highly simple synthesis of benzofuran derivatives.

Tetracyclic skeletons combining an imidazo[1,2-a]pyridine moiety with a quinoline framework such as pyrido[2′,1′:2,3]imidazo[4,5-b]quinoline are stimulating increasing interests since they are close isosteres of a series of powerful antiproliferative compounds. In this paper, we report a novel methodology for the synthesis of pyrido[2′,1′:2,3]imidazo[4,5-c]quinolines through one-pot sequential reactions of commercially available or readily obtainable 2-aminopyridines, 2-bromophenacyl bromides, aqueous ammonia, and aldehydes. Moreover, dihydropyrido[2′,1′:2,3]imidazo[4,5-c]quinolines could also be obtained in a similar manner by using various ketones as the substrates in place of aldehydes. Notably, the whole procedure combines condensation/amination/cyclization reactions in one pot to give complex compounds in a simple and practical manner. Compared with literature methods, the synthetic strategy reported herein has the advantages of readily available starting materials, structural diversity of products, good functional group tolerance, and obviation of step-by-step operations.

An efficient synthesis of substituted indolizine and its benzo derivatives, pyrrolo[1,2-a]quinolines and pyrrolo[2,1-a]isoquinolines, by the reaction of allenyl ketones with α-bromo carbonyl compounds and pyridines (quinoline or isoquinoline) under mild conditions without an added oxidant other than molecular oxygen from air was developed. Notably, allenyl ketones with or without a substituent attached to the internal position of the allene moiety afforded indolizine derivatives with different substitution patterns.

An efficient one-pot synthesis of aminonaphthopyranones through the tandem reaction of 2-(4-hydroxybut-1-ynyl)benzonitriles with Reformatsky reagents has been developed. Using a similar strategy, aminonaphthochromenones were obtained smoothly starting from 2-[(2-hydroxyphenyl)ethynyl]benzonitriles. Furthermore, by taking advantage of the versatile reactivity of the amino group, structural manipulations of aminonaphthopyranone were readily undertaken to give naphthopyranone, 10-hydroxynaphthopyranone and a functionalized 1,1′-binaphthyl of potential interest for synthetic and medicinal chemistry studies.

An efficient synthesis of diversely substituted quinazolines and 1,2,3,4-tetrahydroquinazolines through copper-catalyzed tandem reactions of the readily available 2-bromobenzyl bromides, aldehydes, and aqueous ammonia or amines has been developed. By using ammonia and simple aliphatic amines as the nitrogen source, the present method provides a versatile and practical protocol for the synthesis of quinazolines and 1,2,3,4-tetrahydroquinazolines.

The efficient syntheses of 3-cyanoquinolin-2-ones, 3-(2-bromobenzyl)-3-cyano-3,4-dihydroquinolin-2-ones, 3-(2-bromobenzyl)quinolin-2-ones, and 12H-chromeno[2,3-b]quinolin-12-ones through copper-catalyzed N- and O-arylation of amides by using readily available 2-bromobenzyl bromides and cyanoacetamides as starting materials were developed.

An environmentally and economically sustainable synthesis of 2-benzoxazyl ketones and 2-benzothiazyl ketones through FeCl₃·6H₂O catalyzed tandem reactions of alkynyl bromides with 2-amino(thio)phenols in [bmim]BF₄ has been developed. Remarkable advantages of this new synthetic strategy include high efficiency, readily available starting materials, and recyclable catalyst and reaction medium.