Addition of organolithium reagents to quinone silyl methyl monoketals. A useful expedient in the synthesis of p-quinols having acid-sensitive groups

Quinone Alkylation Using Organocadmium Reagents: A General Synthesis of Quinols

“…Secondary dialkylcadmium reagents (isopropyl and sec -butyl) gave 46% 2e and 58% 2f, while diarylcadmium (R = phenyl) gave 75% 2g . Benzoquinone-derived quinols 2a − g showed the characteristic 1 H and 13 C NMR spectra previously reported. , All reactions shown in Scheme where devoid of bisaddition and hydroquinone byproducts as determined by GC−MS and 1 H NMR. These results are in stark contrast to organolithium and Grignard additions to benzoquinone, where secondary alkyl and aryl additions result primarly in quinone reduction …”

“…After a period of stirring, the reaction mixtures were poured into water and extracted with dichloromethane. Purification of the crude product using base-washed silica gel chromatography afforded the quinols as shown in Scheme . Organocadmium alkylation of benzoquinone 1 is of general applicability with quinol yields ranging from 46 to 89%.…”

“…Heat was then applied, and the mixture was refluxed for 45 min. A qualitative test for the presence of Grignard reagent was then performed using a previously reported procedure …”

“…The solvent was removed under reduced pressure. The crude products were purified by flash chromatography (base washed silica gel, 30% acetone/hexane) , Reactions involving 1,4-naphthoquinone and 9,10-anthraquinone gave compounds having the following properties.…”

1,4-Addition of Lithium Organyls to para-Quinols / Structure Determination of 2,6-Di-tert-butyl-4-hydroxy-4,5-diphenylcyclohex-2-en-1-one

“…5 % of the applied phenyl lithium); 2-4 (petroleum ether:benzene = 10:1. (2) 1757 (3) 44(1) C (6) 6638 (3) 4448 (2) 1859 (3) 46(1) C (7) 3804 (4) 2996 (2) 546(4) 62(1) C (8) 3213 (4) 3282 (3) 1408 (4) 92(2) C (9) 2832 (4) 3131 (2) -819(4) 88(2) C (10) 4006 (5) 2174 (2) 733 (6) 127(2) C (ll) 8123 (3) 2933 (2) 532 (3) 43(1) C ( 12) 8482 (4) 2352 (2) 1376 (3) 52(1) C (13) 9433 (4) 1869 (2) 1434 (4) 62(1) C ( 14) 10047 (4) 1964 (2) 664 (4) 64(1) C (15) 9683 (4) 2528 (2) -183(4) 61(1) C ( 16) 8734 (4) 3005 (2) -232 (3) 49(1) C ( 17) 8898 (4) 4334 (2) 1868 (3) 47(1) C (18) 10097 (4) 4044 (2) 2608(4) 59(1) C ( 19) 11219 …”