Aryl, hetaryl, and ferrocenyl thioketones as versatile building blocks for exploration in the organic chemistry of sulfur

GRAPHICAL ABSTRACT

ABSTRACT

Methods for the synthesis of hetaryl and ferrocenyl thioketones as well as applications of this class of organic sulfur compounds in the synthesis of both sulfur-containing and sulfur-free organic products are summarized. The most important applications relate to [2+2]-, [3+2]-, and [4+2]-cycloadditions. Aromatic thioketones react with diazomethane at −70°C, and the formed 1,3,4-thiadiazolines can be used as convenient precursors of reactive thiocarbonyl S-methanides. In contrast, the hetaryl thioketones do not form this type of cycloadducts. Reactions of hetaryl thioketones with thiocarbonyl S-methanides are proposed to occur via a stepwise diradical mechanism. Aryl and hetaryl thioketones react as prone heterodienophiles with cyclic and acyclic dienes. The first asymmetric synthesis of dihydrothiopyranes from aryl and hetaryl thioketones was performed using a l-proline-derived organocatalyst. Hetaryl thiochalcones are useful heterodienes for the preparation of hetaryl-substituted dihydrothiopyrans.

KEYWORDS:

• Hetaryl ketones
• hetaryl thioketones
• ferrocenyl derivatives
• ethylene derivatives
• sulfur heterocycles

Funding

The authors acknowledge financial support by the National Science Center (Cracow, Poland) (Grant Maestro–3 (Dec–2012/06/A/ST5/00219) for GM) and Ministry of Science and Higher Education, Poland (‘Iuventus Plus’ programme realized in the period 2015–2017, project number: 0008/IP3/2015/73 for ŁA).