
TY  - JOUR
A1  - Collins, DJ 
A1  - Rutschmann, SB 
T1  - Enolic Ortho Esters. II. Tandem Nucleophilic Electrophilic Dimethylation of 4',4'-Dimethyl-3,4,5,8-tetrahydrospiro[2H-1-Benzopyran-2,2'-[1,3]dioxolan]
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1989
VL  - 42
IS  - 9
SP  - 1447
EP  - 1454
KW  - 
UR  - https://doi.org/10.1071/CH9891447 
N2  - Reaction of 4&#8242;,4&#8242;-dimethyl-3,4,5,8-tetrahydrospiro[2H-1-benzopyran-2,2&#8242;-[l,3]dioxolan](9) with methylmagnesium iodide in benzene or toluene at 40º gave the iodomagnesium enolate acetal (10) which upon in situ reaction with methyl iodide afforded 56% of pure 6 &#958;-methyl- 6-[2&#8242;-(2&#8243;,4&#8243;,4&#8243;-trimethyl-1&#8243;,3&#8243;-dioxolan 2&#8243;yl)ethyl]cyclohex-3-en-one (11), the product of tandem nucleophilic/electrophilic dimethylation . Aqueous ammonium chloride workup of the iodomagnesium  enolate (10) gave 6-[2&#8242;-(2&#8243;,4&#8243;,4&#8243;-trimethyl-1&#8243;,3&#8243;-dioxolan 2&#8243;yl)ethyl] cyclohex-3-en-1-one (7). Some further transformations of the methylated keto acetal (11) are described. 
ER  -

