A Fragrant Introduction to Terpenoid Chemistry

by Sell, Charles S.

• ISBN13: 9780854046812
• ISBN10: 085404681X
• Format: Paperback
• Copyright: 2003-11-01
• Publisher: Royal Society of Chemistry

Summary

Terpenoids play an important part in all our lives, from Vitamin A and hormones to perfumes and pharmaceuticals. This book provides an introduction to terpenoid chemistry, concentrating on the lower terpenoids, but the basic principles taught are also the foundation for the chemistry of the higher terpenoids. Coverage includes: the biogenesis of terpenoids; some of the history of the field; the principles of structural determination; and the importance of stereochemistry and stereoselective synthesis. Carbocation chemistry is introduced, as are the principles of total and partial synthesis. Finally, industrial chemistry (both discovery chemistry and chemical process development) is discussed, using the volatile terpenoids of perfumery to illustrate basic concepts. Ideal as both an introduction to terpenoid chemistry and as a refresher course, A Fragrant Introduction to Terpenoid Chemistry, with its real-life problems and appreciation of the relevance of chemistry to everyday life, will prove invaluable to students, lecturers and industrialists alike.

Table of Contents

Acknowledgements	xvii
Background	1	(18)
Definitions and Classification	1	(2)
The Isoprene Rule	3	(1)
Terpenoid Nomenclature	4	(2)
The Role of Terpenoids in Nature	6	(6)
Extraction and Use of Terpenoids	12	(5)
Natural Inspiration	17	(2)
References	18	(1)
Biosynthesis	19	(24)
Introduction	19	(1)
Enzymes and Coenzymes	20	(5)
Adenosine Triphosphate (ATP)	21	(1)
Nicotinamide Adenine Dinucleotide Phosphate (NADP/NADPH)	22	(1)
Coenzyme A (CoA)	23	(1)
(Co)enzymes in Summary	24	(1)
Biosynthesis of C5 Pyrophosphates	25	(3)
Linear Terpenoids via Head-to-Tail Coupling	28	(1)
Cyclic Terpenoids Through Carbocation Chemistry	28	(6)
Monoterpenoids from Geranyl Pyrophosphate	34	(4)
Sesquiterpenoids from Cis, Trans-Farnesyl Pyrophosphate with Initial Closure at the 6,7-Double Bond	38	(1)
Sesquiterpenoids from Cis, Trans-Farnesyl Pyrophosphate with Initial Closure at the 10,11-Double Bond	39	(1)
Sesquiterpenoids from Trans, Trans-Farnesyl Pyrophosphate	39	(1)
Diterpenoids	40	(1)
Tail-to-Tail Coupling -- Triterpenoids and Steroids	41	(1)
Tetraterpenoids and Carotenoids	42	(1)
Reference	42	(1)
Linear and Monocyclic Monoterpenoids	43	(22)
Structural Determination	44	(1)
Myrcene	44	(4)
Other Monoterpenes	48	(1)
Citral	49	(5)
Geraniol	54	(2)
Linalool	56	(4)
Citronellol and Citronellal	60	(2)
Terpineol	62	(3)
Menthol and Carvone	65	(32)
Types of Isomerism	66	(10)
Structural Isomerism	66	(1)
Positional Isomerism	67	(1)
Geometrical Isomerism	67	(1)
Conformational Isomerism	68	(3)
Stereoisomerism	71	(5)
Mint Components	76	(2)
Carvone	78	(5)
Menthol	83	(10)
Determination of Absolute Stereochemistry	93	(4)
References	96	(1)
Bicyclic Monoterpenoids	97	(38)
Bicyclic Monoterpenoids	97	(3)
Two Commercial Syntheses of Bicyclic Monoterpenoids	100	(2)
Chemical Puzzle Number 1	102	(1)
Chemical Puzzle Number 2	103	(1)
Chemical Puzzle Number 3	104	(1)
The Fundamentals of Carbocation Chemistry	104	(16)
Reaction Type 1 -- Elimination	104	(1)
Reaction Type 2 -- Solvolysis	105	(1)
Reaction Type 3 -- H-shift	106	(1)
Reaction Type 4 -- C-shift	107	(4)
Driving Force 1 -- Cation Stability	111	(2)
Driving Force 2 -- Ring Strain	113	(1)
Driving Force 3 -- Steric Strain	114	(1)
Selectivity Factor 1 -- Electron Density	115	(1)
Selectivity Factor 2 -- Polarisability	116	(2)
The Trans-Anti-Periplanar Rule	118	(2)
Explanations	120	(6)
Explanation for Chemical Puzzle Number 1	120	(3)
Explanation for Chemical Puzzle Number 2	123	(2)
Explanation for Chemical Puzzle Number 3	125	(1)
Previous Chemistry Revisited
Carvone	126	(1)
Biogenesis of the Acorane Skeleton	126	(2)
Biogenesis of the Guaiane Skeleton	128	(1)
Biogenesis of the Skeleton Caryophyllane and Himachalane Skeleta	129	(1)
Biogenesis of the Steroid Skeleton	130	(1)
An Anionic Transannular Reaction	131	(3)
A Neutral Transannular Reaction	134	(1)
Precious Woods	135	(42)
Sandalwood	135	(20)
Synthesis of α-Santalol	138	(2)
Stereochemistry of the Aldol Condensation	140	(2)
Synthesis of Z-α-Santalol	142	(1)
The Wittig and Wittig-Schlosser Reactions	143	(2)
Synthesis of β-Santalol	145	(2)
The Exo-effect	147	(1)
The Wittig Reaction with Stabilised Ylids	148	(2)
The Wadsworth--Emmons or Wittig-Horner Reaction	150	(1)
Sandalwood Substitutes	150	(4)
Alkylation of α, β-Unsaturated Ketones	154	(1)
Cedarwood	155	(22)
Total Synthesis of α-Atlantone	156	(2)
Regioselectivity of Isoprene in Friedel--Crafts and Diels--Alder chemistry	158	(1)
Synthesis of α-Atlantone from d-Limonene	159	(1)
Tagetones, Filifolone and Minor Components of Atlas Cedar-wood	160	(1)
α-Atlantone and Deodarone	161	(2)
Cedrol and Cedrene	163	(2)
Friedel--Crafts Acylation of Cedrene	165	(3)
Anomalous Behaviour of Cedrene under Friedel--Crafts Conditions	168	(2)
Thujopsene	170	(3)
Another Anomaly, Vilsmeier--Haack--Arnold Formylation of δ-Selinene	173	(1)
References	174	(3)
Other Woody Odorants	177	(52)
Vetiver	178	(20)
Initial Structural Determination of the Vetivones	178	(1)
The Initial Structural Determination Disproved	179	(4)
The Correct Structure of β-Vetivone Established	183	(1)
Bloom's Synthesis of the Decalindienone	184	(2)
The Santonin Rearrangement	186	(4)
Marshall and Johnson's Total Synthesis of β-Vetivone	190	(3)
Stork's Total Synthesis of β-Vetivone	193	(4)
Other Vetiver Components	197	(1)
Patchouli	198	(5)
Pine (Himalayan)	203	(11)
Synthesis of Longifolene	204	(4)
Acid Catalysed Rearrangement of Longifolene	208	(2)
Reactions of Isolongifolene	210	(2)
Reaction of Longifolene with Bromotrichloromethane	212	(2)
Cloves and Hops	214	(15)
The Synthesis of Caryophyllene	215	(5)
Acid Catalysed Rearrangement of Caryophyllene	220	(4)
Acid Catalysed Rearrangement of Isocaryophyllene	224	(1)
Synthesis of Humulene	225	(1)
References	226	(3)
Degradation Products	229	(40)
Ambergris	229	(16)
Degradation of Ambreine	231	(3)
Ambergris Materials from Other Natural Products	234	(2)
Clary Sage	236	(3)
Labdanum	239	(3)
Total Synthesis	242	(1)
Jeger's Ketal from Manool	242	(3)
Carotenoids	245	(24)
Vitamin A -- The Chemistry of Sight	245	(1)
7-Transmembrane G-coupled Receptor Proteins	246	(6)
Violets, Roses, Orris, Osmanthus, Geranium, Grapes, Vanilla, Raspberries, Passionfruit and Tea -- The Chemistry of Ionones and Related Compounds	252	(1)
Ionones	253	(3)
Damascones	256	(1)
Theaspiranes and Vitispiranes	257	(2)
Irones -- The Chemistry of Iris	259	(7)
References	266	(3)
Commercial Production of Terpenoids	269	(40)
Difference Between Academic and Commercial Syntheses	270	(1)
Constraints on Commercial Processes	270	(11)
Safety	271	(1)
Environment	272	(3)
Purity	275	(1)
Reproducibility	276	(1)
Capacity	277	(1)
Cost	278	(2)
Sustainability	280	(1)
Experimental Design	281	(4)
Fragrance Ingredients Derived from Terpenoids	285	(15)
Interconversion of the Five Key Terpenoids	287	(1)
Commercial Aspects	288	(1)
Evolution of Petrochemical Routes to Citral	289	(6)
Isoprene to Citral	295	(2)
Citral, Geraniol etc. from Turpentine	297	(3)
Product Trees	300	(5)
Conclusion	305	(4)
References	307	(2)
Discovery and Design of Novel Molecules	309	(38)
Why Search for Novel Molecules?	310	(1)
Molecule Discovery Through Random Screening	311	(1)
Nature as a Source of Novel Molecules	312	(1)
Design Through Statistics	312	(6)
Design Through Understanding	318	(1)
Perfumery	318	(4)
Requirements of Fragrance Ingredients	322	(12)
Safety	322	(1)
Safety -- In Use	322	(2)
Safety -- In the Environment After Use	324	(1)
Odour	324	(1)
Odour Character	325	(3)
Odour Intensity	328	(1)
Odour Tenacity	329	(1)
Mechanism of Olfaction	330	(3)
Performance in Formulae	333	(1)
Performance in Product	333	(1)
Additional Benefits	334	(1)
Availability	334	(1)
From Natural to High Performance, Examples of Discovery of Terpenoid Odorants	334	(9)
Examples of Natural Fragrance Ingredients	335	(1)
Examples of Analogues of Natural Fragrance Ingredients	336	(1)
Examples of Designed Fragrance Ingredients	337	(6)
Conclusion	343	(4)
References	344	(3)
Bibliography	347	(4)
Problems	351	(18)
Solutions to Problems	369	(26)
Subject Index	395	(14)
Author Index	409