Synthesis and [3+2] cycloaddition reaction of 3-[(trimethylsilylmethylamino)(methylthio)-methylene]heterocyclic compounds

✍ Scribed by Yoshinori Tominaga; Satoshi Takada; Shinya Kohra; Yasumitsu Shigemitsu

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2001
• Tongue: English
• Weight: 125 KB
• Volume: 38
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570380519

✦ Synopsis

Abstract

3‐[(Trimethylsilylmethylamino)(methylthio)]methylene‐2‐coumaranone (4a) and 1‐methyloxindole (4b), readily prepared by reactions of the corresponding bis(methylthio)methylene heterocyclic compounds (2a, b), with (trimethylsilylmethyl)amine (3), were found to be synthetic equivalents of heterocyclic alkylidene‐azomethine ylides. Reactions of 4a, b with reactive heterodipolarophiles such as aldehydes and ketones and reactive alkenes in the presence of cesium fluoride gave the 1,3‐dipolar cycloadducts, 3‐(2‐oxazoli‐dinylidene)‐oxindole and ‐coumaran‐2‐one derivatives (8a‐j, 9a‐h), as well as pyrrolylidenecoumaran‐2‐one and oxindole derivatives (12‐15,17,18), via the 1,3‐elimination of (methylthio)trimethylsilane.