Many Maruoka chiral phase-transfer catalysts are based on quaternizing the azepine nitrogen with substituted binapthyl and/or diphenyl groups to get a twisted asymmetric structure. The chiral phase-transfer catalyst described in this patent is atypical in that one of the alkyl groups is a methyl group.
Usually when a methyl group is one of the four alkyl groups that quaternizes a nitrogen, the resulting quat is “accessible” and can make a tight ion pair. In theory, tighter ion pairs can enhance chiral recognition in chiral PTC applications. It is not clear if there is any effect at all of accessibility of the positive charge of the nitrogen in this case since there is so much other steric hindrance on the quat.
Now contact Marc Halpern of PTC Organics Inc. to benefit from the highly specialized expertise in industrial phase-transfer catalysis to improve your choice of phase-transfer catalyst and other PTC process parameters.
About Marc Halpern
Dr. Halpern is founder and president of PTC Organics, Inc., the only company dedicated exclusively to developing low-cost high-performance green chemistry processes for the manufacture of organic chemicals using Phase Transfer Catalysis. Dr. Halpern has innovated PTC breakthroughs for pharmaceuticals, agrochemicals, petrochemicals, monomers, polymers, flavors & fragrances, dyes & pigments and solvents. Dr. Halpern has provided PTC services on-site at more than 260 industrial process R&D departments in 37 countries and has helped chemical companies save > $200 million. Dr. Halpern co-authored five books including the best-selling “Phase-Transfer Catalysis: Fundamentals, Applications and Industrial Perspectives” and has presented the 2-day course “Practical Phase-Transfer Catalysis” at 50 locations in the US, Europe and Asia.
Dr. Halpern founded the journal “Industrial Phase-Transfer Catalysis” and “The PTC Tip of the Month” enjoyed by 2,100 qualified subscribers, now beyond 130 issues. In 2014, Dr. Halpern is celebrating his 30th year in the chemical industry, including serving as a process chemist at Dow Chemical, a supervisor of process chemistry at ICI, Director of R&D at Sybron Chemicals and founder and president of PTC Organics Inc. (15 years) and PTC Communications Inc. (20 years). Dr. Halpern also co-founded PTC Interface Inc. in 1989 and PTC Value Recovery Inc. in 1999. His academic breakthroughs include the PTC pKa Guidelines, the q-value for quat accessibility and he has achieved industrial PTC breakthroughs for a dozen strong base reactions as well as esterifications, transesterifications, epoxidations and chloromethylations plus contributed to more than 100 other industrial PTC process development projects.
Dr. Halpern has dedicated his adult life to his family and to phase-transfer catalysis (in that order!).
