Which sequence of steps describes the best synthesis of 2-methyl-3-pentanone?

Question

Which sequence of steps describes the best synthesis of 2-methyl-3-pentanone? (A) (1) 1-Propanol +( CH 3)2 CHMgBr, diethyl ether (2) H 3 O + (3) PCC , CH 2 Cl 2 (B) (1) 1-Propanol + Na 2 Cr 2 O 7, H 2 SO 4, H 2 O, heat (2) SOCl 2 (3) ( CH 3)2 CHCl , AlCl 3 (C) (1) 1-Propanol + PCC , CH 2 Cl 2 (2) ( CH 3)2 CHLi, diethyl ether (3) H 3 O + (4) Na 2 Cr 2 O 7, H 2 SO 4, H 2 O, heat (D) (1) 2-Propanol + Na 2 Cr 2 O 7, H 2 SO 4, H 2 O, heat (2) CH 3 CH 2 CH 2 Li, diethyl ether (3) H 3 O + (4) PCC , CH 2 Cl 2

Tardigrade Admin · Accepted Answer

Correct answer is (c) (1) 1-Propanol + PCC , CH 2 Cl 2 (2) ( CH 3)2 CHLi, diethyl ether (3) H 3 O + (4) Na 2 Cr 2 O 7, H 2 SO 4, H 2 O, heat

Q. Which sequence of steps describes the best synthesis of 2-methyl-3-pentanone?

(1) 1-Propanol $+ (C H_{3})_{2} C H M g B r$ , diethyl ether
(2) $H_{3} O^{+}$
(3) $PCC, C H_{2} C l_{2}$

(1) 1-Propanol $+ N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat
(2) $SOC l_{2}$
(3) $(C H_{3})_{2} C H Cl, A lC l_{3}$

(1) 1-Propanol + $PCC, C H_{2} C l_{2}$
(2) $(C H_{3})_{2} C H L i$ , diethyl ether
(3) $H_{3} O^{+}$
(4) $N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat

(1) 2-Propanol $+ N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat
(2) $C H_{3} C H_{2} C H_{2} L i$ , diethyl ether
(3) $H_{3} O^{+}$
(4) $PCC, C H_{2} Cl 2$

Correct answer is (c) (1) 1-Propanol + $PCC, C H_{2} C l_{2}$
(2) $(C H_{3})_{2} C H L i$ , diethyl ether
(3) $H_{3} O^{+}$
(4) $N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat

Q. Which sequence of steps describes the best synthesis of 2-methyl-3-pentanone?

(1) 1-Propanol +(CH3​)2​CHMgBr, diethyl ether (2) H3​O+ (3) PCC,CH2​Cl2​

(1) 1-Propanol +Na2​Cr2​O7​,H2​SO4​,H2​O, heat (2) SOCl2​ (3) (CH3​)2​CHCl,AlCl3​

(1) 1-Propanol + PCC,CH2​Cl2​ (2) (CH3​)2​CHLi, diethyl ether (3) H3​O+ (4) Na2​Cr2​O7​,H2​SO4​,H2​O, heat

(1) 2-Propanol +Na2​Cr2​O7​,H2​SO4​,H2​O, heat (2) CH3​CH2​CH2​Li, diethyl ether (3) H3​O+ (4) PCC,CH2​Cl2

Correct answer is (c) (1) 1-Propanol + PCC,CH2​Cl2​ (2) (CH3​)2​CHLi, diethyl ether (3) H3​O+ (4) Na2​Cr2​O7​,H2​SO4​,H2​O, heat

(1) 1-Propanol $+ (C H_{3})_{2} C H M g B r$ , diethyl ether
(2) $H_{3} O^{+}$
(3) $PCC, C H_{2} C l_{2}$

(1) 1-Propanol $+ N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat
(2) $SOC l_{2}$
(3) $(C H_{3})_{2} C H Cl, A lC l_{3}$

(1) 1-Propanol + $PCC, C H_{2} C l_{2}$
(2) $(C H_{3})_{2} C H L i$ , diethyl ether
(3) $H_{3} O^{+}$
(4) $N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat

(1) 2-Propanol $+ N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat
(2) $C H_{3} C H_{2} C H_{2} L i$ , diethyl ether
(3) $H_{3} O^{+}$
(4) $PCC, C H_{2} Cl 2$

Correct answer is (c) (1) 1-Propanol + $PCC, C H_{2} C l_{2}$
(2) $(C H_{3})_{2} C H L i$ , diethyl ether
(3) $H_{3} O^{+}$
(4) $N a_{2} C r_{2} O_{7}, H_{2} S O_{4}, H_{2} O$ , heat