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18.2.4.1.7.2 Variation 2: Silane-Induced Cleavage of Carbamates

DOI: 10.1055/sos-SD-018-00070

Braverman, S.; Cherkinsky, M.; Birsa, M. L.Science of Synthesis, (200518111.

Unlike carbamates, N-silylated carbamic acid derivatives 105, prepared by treatment of acid chlorides, anhydrides, or esters either with (chloroalkyl)silanes and triethylamine or with mono- or bis(trimethylsilyl)acetamide, undergo an irreversible β-elimination to give isocyanates and the corresponding silicon compounds 106 under relatively mild conditions between 20 and 120°C (Scheme 66).[‌358‌,‌359‌] Since the isocyanate and the product 106 undergo neither a reverse reaction nor, to any appreciable extent, side reactions, even sensitive or very reactive isocyanates can be obtained in 7095% yields.

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Meeee 8 Meeeeeeeeee ee Meeeeeeeeee eeee Meeeeeeeee eee Meeeeeeeeeeeeeeee[‌888‌,‌888‌,‌888‌,‌888‌]

Meeee M8 M8 M8 e Meee (°M) Meee (e) Meeeee (%) Mee
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8 Me Me Me 8 888888 8.8 88 [‌888‌]
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8 Me Me Me 8 888888 8.8 88 [‌888‌]
8 8-Mee Me M 8 ee 88.8 88e [‌888‌]
8 8-Mee Me Me 8 ee 88.8 8e [‌888‌]
8 8-Mee e-Me M 8 ee 88.8 88e [‌888‌]
88 8-Mee 8-M8MM8M8 Me 8 ee 88.8 88e [‌888‌]

e Meeeeeee eeeee ee eeeeeeeeee.

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Mee eeeeee eee eee eeeeeeeee ee eeeee eee eeee eeeeeeeeeee ee eeeeeeeeeeeee ee M-eeeeeeeeeeeeeee eee eeee eeee eeeeeeee ee eeee eeeeeeeeeee, eeeee eee ee eeeeee ee eeeeeeeeeee ee M-eeee-M-eeeeeeeeeeeeeee.[‌888‌] Meeeeeeee, eeee eeeee- eee eeeeeeeeeeeeeeeeeeeeee eee ee eeeeeeeee eeeeee, eee eeeeeeeeee eeeeeeeeeee ee eee eeeee eeeeeee ee M- eee M-eeeeeeeeeeeeee eeeeeeeeeeeee (888 eee 888) eeeeeeee eee eeeeeeeeeeeee eeeeeeee eeeeeeeeeee ee eeeeeeeee eeeeee.[‌888‌] Meee eeeeeeee eeee e eeeee eeeeeeeeeeeee eeeeeee eee eee eeeeeee ee eeeeeeeee eeeee eee eeeeeeeeeee eeeeeeeeee (Meeeee 88). Meee eeeeeeee, eeeeeeeeeeee eee eeee eeeeeeeeee ee e eeee eee eeeeeeeee eeeeeee eee eee eeeeeeeee eeeeeeee eeeeeeeee ee eeeeeeeeeee.[‌888‌] Mee eeeeeeee eeeeeeee eeeeeee ee 88 ee 8°M ee eeeeeeeeeeeeeee ee eee eeeeeeee ee e eeeeeeee eeeee eeee. M eeeeeee ee eeeeeeeee eee eeeeeeee eeeeeeeeee, eeeeeeeee M-(eeee-eeeeeeeeeeeeee)eeeeeeeeee, eeeee eeeee eeeee eeeeeeeeee eee eeeeeee eee eeeeeeeeeeeee eeeeeeeeeee, eeeee eee eeeeeee ee eeee eeee eeeeee ee eeeeee eeeee ee eeee ee eeeeeeeee eeeeee.

Meeeee 88 Meeeeeee Meeeeeeeeee eee Meeeee-Meeeeee Meeeeeee ee Meeeeeee Meeeeeeeee[‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeee Meeeeeeeee (888, M8=Me); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeee ee eeeeee M-eeeeeeeeeeeeee (88.8e, 8.8eee) eee MeMeMe8 (88.8eM, 8.888eee) eee eeeeee ee 888888°M eeeee eee eeeeeeeee ee MMe eee eeeeee (ee. 8.8e); eeee eee eeeeeee eee eeeeeeeee ee eeeeeeeeeee eeeeeeee ee eeee eee eeeeeee; eeeee: 8.8e (88%); ee 8888°M.

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