Trimethylsilyloxy isocyanate

Die Reaktion von 1,2-Epoxy-cyclohexan mit Cyan-trimethyl-silan in Gegenwart von katalytischen Mengen Zinkchlorid fiihrt zur Bildung von 2-Isocyan-1-trimethylsilyloxy-cyclohexan, das sich mit Ammoniumchlorid in Methanol/Wasser (9 1) zu 2-Isocyan-l-hydroxy-cyclohexanol desilylieren laflt katalytische Hydrierung ergibt dann 2-Methylami-no-l-hydroxy-cyclohexan1 (vgl. S. 1188) ... 

Some attention has been paid in our group to 1,3-diazadienes while working with trimethylsilyl imines, since these reagents allowed us to readily prepare a variety of 2-trimethylsilyloxy- and 2-trimethylsilylthio-1,3-dienes 357 (89S228) (Scheme 79). We first tested their potential as heterodienes toward aromatic isocyanates and found that treatment of a dichloromethane solution of 357 and isocyanate at room temperature resulted in a clean conversion into triazinedione and 4-thioxotriazinone derivatives 358 in 84-96% yield. 

A new sulphamoylation agent, N-carbo(trimethylsilyloxy)sulphamoyl chloride (286), prepared by the reaction of (trimethylsilyl)ethanol with chlorosulphonyl isocyanate followed by the elimination of ethylene, has been reported297 (equation 89). This reagent has been used successfully in the preparation of 3-amino-4-A/-alkyl-5-aryloxy-l,2,4,6-thiatriazine-1,1-dioxide (288) (equation 90) by reaction of 286 with N-cyano-N-alkyl pseudoureas (287). The 2-N-alkyl isomer of 288 has also been synthesized. 

Cycloaddition of aroyl isocyanates and trimethylsilyl ketene generates 4-trimethylsilyloxy-l,3-oxazin-6-ones 29 in situ, which smoothly react with cycloalkanone enamines to give 3,4-cycloalkeno-2-pyridones 30 [87] ... 

TMEDA N,N,N, N -Tetramethylethylenediamine TMI 3-Isopropenyl-a,a-dimethylbenzene isocyanate TMSHEMA 2-(Trimethylsilyloxy)ethyl methacrylate VAc Vinyl acetate VE Vinyl ether... 

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