A rare diversion

Ring-opening mechanism of disilacyclopropylidenoids and trisilacyclopropylidenoid: A theoretical study

“…The theoretical results indicate that the ring-opening reaction of 1-bromo-1-lithiosilirane (1) to the complex of 2-silaallene (3) can occur in a stepwise fashion with the intermediacy of a free silacyclopropylidene, whereas that of 2-bromo-2-lithiosilirane (2) to the complex 1-silaallene (4) can proceed in a concerted fashion. Moreover, the ring-opening reaction of 1 is endothermic by 11.0 kcal/mol, while that of 2 is highly exothermic, by 44.3 kcal/mol.…”

Aromaticity and Activation Strain Analysis of [3 + 2] Cycloaddition Reactions between Group 14 Heteroallenes and Triple Bonds

“…[2][3][4] In contrast, their heavier analogues EdCdE 0 (E, E 0 = Si, Ge, Sn, N, P, As) have received much less attention because they have been only postulated as transient intermediates for a long time. However, heavier heteroallenes, such as phosphaallenes PdCdX 0 and R 3 PdCdPR 3 or metallaallenes EdCdC (E = Si, Ge) can be successfully synthesized as stable or transient derivatives by using bulky substituents, [5][6][7][8][9][10][11][12][13] which kinetically stabilize the reactive double bonds.…”

“…This growing interest is mainly due to the development of efficient methods for the preparation of allenes based on either classical organic chemistry or organometallic reagents. − In contrast, their heavier analogues ECE′ (E, E′ = Si, Ge, Sn, N, P, As) have received much less attention because they have been only postulated as transient intermediates for a long time. However, heavier heteroallenes, such as phosphaallenes PCX′ and R 3 PCPR 3 or metallaallenes ECC (E = Si, Ge) can be successfully synthesized as stable or transient derivatives by using bulky substituents, − which kinetically stabilize the reactive double bonds.…”