The Vespiary

The Hive => Novel Discourse => Topic started by: tropine on October 01, 2003, 07:55:00 AM

Title: titanium (IV) isoperoxide for large scale?
Post by: tropine on October 01, 2003, 07:55:00 AM

If one were to want to aminate a mole of ketone, how much titanium (IV) would they use?  It looks to be a catalyst of sorts, but all write ups so far claim that double the molar ratio of ketone to titanium (IV) is used (ie 10 mmol of ketone and 20 mmol (5.9 mL) of titanium).  I doubt that one would use 600 mL of titanium (IV) for the 1 mole of ketone!

Title: Reductive Amination w/ Titanium(IV)Isopropoxide
Post by: Rhodium on October 01, 2003, 11:35:00 AM

You need as many moles of Ti⁴⁺ as the number of moles of methylamine added, as they bind to each other in a 1:1 fashion. This complex then in turn adds to the ketone forming a so-called (methylamino)carbinolatotitanium(IV) complex as an intermediate which is reduced either directly or via transient iminium species.

See the following articles for details:

Reductive Alkylations of Dimethylamine Using Titanium(IV)Isopropoxide and Sodium Borohydride:
An Efficient, Safe, and Convenient Method for the Synthesis of N,N-Dimethylated Tertiary Amines
Sukanta Bhattacharyya

J. Org. Chem. 60, 4928-4929 (1995) (https://www.thevespiary.org/rhodium/Rhodium/pdf/redamin.nabh4-ti4-me2nh.pdf)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/redamin.nabh4-ti4-me2nh.pdf)

A New Method for the Synthesis of alpha-Substituted Phenethylamines via Titanium Amide Complexes

Synthesis 238-240 (1988) (https://www.thevespiary.org/rhodium/Rhodium/pdf/titanium.amide.amphetamines.pdf)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/titanium.amide.amphetamines.pdf)