Synthesis of a 2H-Azirine by [1 + 2] Cycloaddition of a Phosphinocarbene with a Nitrile and Its Ring-Expansion to a 1,2λ5-Azaphosphete

✍ Scribed by Gilles Alcaraz; Dr. Ulrich Wecker; Dr. Antoine Baceiredo; Dr. Françoise Dahan; Dr. Guy Bertrand

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 275 KB
• Volume: 34
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.199512461

✦ Synopsis

mation of the ( Z ) isomer supports the assumption that in compound 13 (and probably also in 12) the substituents at the noncoordinated C=C double bond are arranged cis. The rhodium-containing product of the reaction of 8 or 13 with acetic acid is the chelate complex 17,[*] which can be reconverted in two steps [a) reaction with HC=CR to give I;14b1 b) "chromatography" of I on chloride-containing A1,0, [' 31] to the starting materials 2 and 3. In this way a cyclic process can be established by which, from HC=CR, RMgX, and CH,CO,H and assisted by the metal, an olefin RCH=CHR' (R = Ph, t B u ; R = Me, CH=CH,) is regio-and stereoselectively formed. trans-[RhH(C=CR)($-O2CCH3)(PiPr,),l

I

Preliminary attempts indicate that the "metallabutatrienes" J [14] behave similarly towards Grignard reagents as the vinylidene complexes 1-3 and that the corresponding vinyl metal derivatives K undergo isomerization reactions as well. Therefore, the expectation is that even higher unsaturated hydrocarbons than 18 could be accessible by a rhodium-assisted C-C coupling procedure. Irans-[RhCI(=C=C=CR,)(PiPr,),l J trans-[Rh(CH=CH,)(=C=C=CR,)(PiPr3)2] K