10.1021/acs.organomet.6b00445.s002 Matthew T. Flynn Matthew T. Flynn Rachel Stott Rachel Stott Victoria L. Blair Victoria L. Blair Philip C. Andrews Philip C. Andrews Loss of Chirality through Facile Lewis Base Mediated Aza-enolate Formation in Na and K (<i>S</i>)‑<i>N</i>‑(α-Methylbenzyl)methallylamides American Chemical Society 2016 n BuM benzene solution anion rearrangement THF complexes 1 Lewis base K amides Na PhCH CH PMDETA TMEDA Lewis donors PhC NMR spectroscopy 2016-08-09 15:54:28 Journal contribution https://acs.figshare.com/articles/journal_contribution/Loss_of_Chirality_through_Facile_Lewis_Base_Mediated_Aza-enolate_Formation_in_Na_and_K_i_S_i_i_N_i_-Methylbenzyl_methallylamides/3555909 Metalation of (<i>S</i>)-<i>N</i>-(α-methylbenzyl)­methallylamine with <i>n</i>BuM (M = Li, Na, or K) in hexane leads to the allylic metal amides [(<i>S</i>)-PhCH­(CH<sub>3</sub>)­N­(CH<sub>2</sub>C­{CH<sub>3</sub>}CHLi)­Li]<sub>6</sub>, <b>1</b>, [(<i>S</i>)-PhCH­(CH<sub>3</sub>)­N­(CH<sub>2</sub>C­{CH<sub>3</sub>}CH<sub>2</sub>)­Na]<sub><i>n</i></sub>, and [(<i>S</i>)-PhCH­(CH<sub>3</sub>)­N­(CH<sub>2</sub>C­{CH<sub>3</sub>}CH<sub>2</sub>)­K]<sub><i>n</i></sub>, respectively. The addition of any Lewis base (here THF, TMEDA, or PMDETA) to the Na and K amides promotes rapid anion rearrangement to the aza-enolate complexes [PhC­(CH<sub>2</sub>)­N­(CH<sub>2</sub>CH­{CH<sub>3</sub>}<sub>2</sub>)­Na]<sub>∞</sub>, <b>2</b>, [PhC­(CH<sub>2</sub>)­N­(CH<sub>2</sub>CH­{CH<sub>3</sub>}<sub>2</sub>)­Na·TMEDA]<sub><i>n</i></sub>, <b>3</b>, [PhC­(CH<sub>2</sub>)­N­(CH<sub>2</sub>CH­{CH<sub>3</sub>}<sub>2</sub>)­Na·PMDETA]<sub><i>n</i></sub>, <b>4</b>, and [PhC­(CH<sub>2</sub>)­N­(CH<sub>2</sub>CH­{CH<sub>3</sub>}<sub>2</sub>)­K]<sub><i>n</i></sub>, <b>5</b>, resulting in loss of chirality. In contrast, the addition of benzene leads exclusively to the 1-aza-allyl complexes [(<i>S</i>)-PhCH­(CH<sub>3</sub>)­N­(CHC­{CH<sub>3</sub>}<sub>2</sub>)­Na]<sub><i>n</i></sub>, <b>6</b>, and [(<i>S</i>)-PhCH­(CH<sub>3</sub>)­N­(CHC­{CH<sub>3</sub>}<sub>2</sub>)­K]<sub><i>n</i></sub>, <b>7</b>, both of which are not observed in the presence of Lewis donors. Doping a benzene solution of <b>7</b> with THF gives the first observation of reorganization to the intermediate 2-aza-allyl anion. All seven complexes have been characterized by NMR spectroscopy, with complexes <b>1</b> and <b>2</b> also being characterized by single-crystal X-ray diffraction. Rearrangement to the aza-enolates <b>2</b> and <b>3</b> is unprecedented under the conditions employed.