Theoretical studies on the intramolecular cyclization of 2,4,6-t-Bu₃C₆H₂P=C: and effects of conjugation between the P=C and aromatic moieties

• Masaaki Yoshifuji and
• Shigekazu Ito

Beilstein J. Org. Chem. 2014, 10, 1032–1036, doi:10.3762/bjoc.10.103

• Abstract The intramolecular C–H insertion of the Mes*-substituted phosphanylidenecarbene [Mes*P=C:] (Mes* = 2,4,6-t-Bu3C6H2) and physicochemical properties of the cyclized product, 6,8-di-tert-butyl-3,4-dihydro-4,4-dimethyl-1-phosphanaphthalene were studied based on ab initio calculations. Whereas the

• : suggests remarkable conjugation effects between the nearly coplanar P=C skeleton and the aryl moiety. Keywords: 3,4-dihydro-1-phosphanaphthalene; intramolecular cyclization; organophosphorus; phosphanylidenecarbene; steric protection; theoretical calculation; Introduction Sterically demanding groups on

• the stabilization of various kinds of unusual phosphorus compounds has been clarified so far [2][3][4]. Phosphanylidenecarbene [RP=C:], a heavier congener of alkylidenecarbene (phosphaisonitrile) has been an intriguing reaction intermediate containing a low-coordinated phosphorus atom, and afforded a