Maruoka patented a new class of spiro chiral phase-transfer catalysts. Previous Maruoka chiral PTC’s had substituted binaphthyl groups on both sides of the nitrogen or substituted biphenyl groups on both sides of the nitrogen. The current class of compounds claimed in this patent has a binaphthyl on one side of the nitrogen and a biphenyl on the other side.
Incorporating a mixed binaphthyl-biphenyl spiro ammonium salt achieves several advantages that include greater steric differentiation, greatly enhanced flexibility in the array of substituents one can envision to achieve stronger chiral recognition, lower cost synthetic route and more.
The patent describes the synthesis and characteristics of 17 mixed Maruoka catalysts with a variety of substituents of which methoxy and 3,4,5-trifluorophenyl are particularly notable.
This patent does not describe examples of the use of these chiral phase-transfer catalysts but one’s imagination can run wild with anticipation of the future impressive enantioselectivities.
If your company can benefit from expert choice of phase-transfer catalyst to achieve the highest performance in the shortest development time, you should consider bringing the in-house PTC course to your company or contact Dr. Marc Halpern of PTC Organics to inquire about PTC Process Consulting or PTC Process Contract Research.
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!).
