How is ketal formed?
Ketals and acetals are formed by reaction of the carbonyl with alcohols such as methanol or ethanol under anhydrous conditions, in the presence of an acid catalyst. It is obvious that many alcohols can be used to generate acetals and ketals, but methanol and ethanol are probably the most common ones used.
What is a ketal product?
A ketal is a functional group or molecule containing the functional group of a carbon bonded to two -OR groups, where O is oxygen and R represents any alkyl group. It is essentially equivalent to an acetal, and often the term acetal is used instead. Ketals and acetals can be used as carbonyl-protecting groups.
Which acid is used for the cleavage of ketal group during the preparation of Ribisin B?
The ketal group in methyl ether 13 was cleaved, under acidic conditions (TFA, THF, H2O), in a similar manner to that used for acetonide 6 (Scheme 2), to form cis-diol 14 (97% yield). The C-1 hydroxyl group group of diol 14 was chemoselectively oxidized to ketone 15 (catalytic TEMPO with Oxone, Scheme 3) (86% yield).
What is the structure of ketal?
A ketal is a compound that has the following general structural formula. R3, R4 = alkyl (In most ketals, R3 = R4; cyclic ketals are an exception.)
What is a ketal in chemistry?
Ketal: The acetal of a ketone. A contraction of ketone and acetal. Although useful to differentiate an aldehyde acetal from a ketone acetal, ‘ketal’ has fallen out of use.
What is ketal example?
Ketal:- When a ketone reacts with ethylene glycol in the presence of dry HCl gas, a cyclic product in formed which is called a ketal.
What is ketal and acetal?
The term ketal is sometimes used to identify structures associated with ketones (both R groups organic fragments rather than hydrogen) rather than aldehydes and, historically, the term acetal was used specifically for the aldehyde-related cases (having at least one hydrogen in place of an R on the central carbon).
What is the difference between acetal and ketal?
Hint : As from the names we can conclude that acetal form is related to aldehydes and the ketal form is related to ketones. These compounds play the great role in organic chemistry mainly in aldehydes and ketones reactions. …
How do you Deprotect ketal?
Acetals and ketals are readily deprotected under neutral conditions in the presence of acetone and indium(III) trifluoromethanesulfonate as catalyst at room temperature or mild microwave heating conditions to give the corresponding aldehydes and ketones in good to excellent yields.
What is cyclic ketal?
A cyclic ketal is a ketal in the molecule of which the ketal carbon and one or both oxygen atoms thereon are members of a ring.
What is ketal English?
Definition of ketal : an acetal derived from a ketone.