In both cases, the cyclic hemiacetal is formed. But: 1). Hydrolysis with diluted acid (LiAlH4 reduction), favors the hemiacetal ring opening and 1,4-butanediol is finally formed. 2). Isopropanol (NaBH4 reduction) has lower pka value than a primary butanol and theoretically cannot open the hemiacetal ring. But in practice, the hemiacetal ring will finally be open during the reaction working up with an aqueous medium. Hint: Please, do not confuse the stability of the said cyclic hemiacetal with the stability of carbohydrates cyclic hemiacetals (pyranoses and furanoses) that are stabilized by intramolecular hydrogen bonds.
In both cases, the cyclic hemiacetal is formed. But: 1). Hydrolysis with diluted acid (LiAlH4 reduction), favors the hemiacetal ring opening and 1,4-butanediol is finally formed. 2). Isopropanol (NaBH4 reduction) has lower pka value than a primary butanol and theoretically cannot open the hemiacetal ring. But in practice, the hemiacetal ring will finally be open during the reaction working up with an aqueous medium. Hint: Please, do not confuse the stability of the said cyclic hemiacetal with the stability of carbohydrates cyclic hemiacetals (pyranoses and furanoses) that are stabilized by intramolecular hydrogen bonds.
1). Hydrolysis with diluted acid (LiAlH4 reduction), favors the hemiacetal ring opening and 1,4-butanediol is finally formed.
2). Isopropanol (NaBH4 reduction) has lower pka value than a primary butanol and theoretically cannot open the hemiacetal ring. But in practice, the hemiacetal ring will finally be open during the reaction working up with an aqueous medium.
Hint: Please, do not confuse the stability of the said cyclic hemiacetal with the stability of carbohydrates cyclic hemiacetals (pyranoses and furanoses) that are stabilized by intramolecular hydrogen bonds.
1). Hydrolysis with diluted acid (LiAlH4 reduction), favors the hemiacetal ring opening and 1,4-butanediol is finally formed.
2). Isopropanol (NaBH4 reduction) has lower pka value than a primary butanol and theoretically cannot open the hemiacetal ring. But in practice, the hemiacetal ring will finally be open during the reaction working up with an aqueous medium.
Hint: Please, do not confuse the stability of the said cyclic hemiacetal with the stability of carbohydrates cyclic hemiacetals (pyranoses and furanoses) that are stabilized by intramolecular hydrogen bonds.
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